Hm... I’ve actually always kind of seen it the other way around! I don’t think sb is telling a white lie just to protect bg’s confidence. Whenever sb says he prefers bg with short hair, I believe he genuinely means it. On the other hand, I’ve gotten the impression that bg favors or feels more attached to his long hair, whether it's due to personal preference or because he thinks fans like it better on him. While this isn’t entirely true—many fans (including myself) love his short hair—bg might not realize this since his long hair has become such an iconic look that garnered a lot of attention from the public.

What stands out to me is how sb handles this. He clearly prefers bg’s short hair, but he’s very cautious about bringing this up to make sure bg doesn’t feel insecure about his long hair. For example, when sb once asked the other members which hairstyle they preferred on bg, all said long hair, so sb held back from sharing his own opinion since it was in the minority. He doesn’t want bg to feel like his long hair is unappreciated, especially if bg himself likes it. It’s like when someone gets a new hairstyle, like bangs, and they’re excited to show it to their partner. If their partner says, 'It looks good, but I liked you better before,’ it can feel disheartening. It might make them think, 'Why can’t you just say it looks good without comparing it to the old style?'

Sb is socially aware and wouldn’t ever want bg to feel bad about his preference for long hair, so he avoids making any negative ccomparisons and is careful not to impose his opinion, especially when bg has long hair. He doesn't tell bg to cut his hair first, but he fully supports him when bg expresses a desire to cut it. For instance, every time bg says, “I want to cut my hair,” sb encourages him, saying, “Then cut it!” He’s careful not to pressure bg into cutting it if he doesn’t want to, making sure it’s bg’s own decision. Once, after sb gave his usual support when bg said he wanted to cut his hair, yj chimed in, saying, “But I think you look good with long hair.” bg then turned to sb and said, “See? He says I look good with long hair.” sb had to explain, “I only told you to cut it because you said you wanted to,” emphasizing that his priority is to support bg’s decisions, not push his own preference.

bg might be a bit sensitive to this because he knows sb prefers his short hair, but sb is careful not to express that preference when bg has long hair, to avoid making him feel uncomfortable. Instead, sb only shares his preference when it’s appropriate—like when bg does cut his hair short—and during those times, sb doesn't hold back, showering him with compliments to reassure him that his short hair is just as appreciated.

I get that sgyv are probably car buddies on overseas schedules too, mainly for practical reasons. It’s easier to stick to the same arrangement they use in Korea rather than having to decide who rides with whom each time, especially to avoid confusion. But when they're abroad, the schedule is usually more relaxed than when they’re back home, so there’s more flexibility. They didn’t need to all leave at the same time since they didn’t have anything else planned for the rest of the day. Plus, when sb suggested bg go back to the hotel first, it shows there were multiple cars available, meaning bg didn’t need to wait for sb to leave with him.

That makes it clear bg asking sb to leave together wasn’t for logistical reasons. It seems more like there was a personal motive behind his request. One reason could be that bg wanted sb’s company. Maybe he just wanted to ride back to the hotel with him or spend more time together so he wouldn’t feel bored or lonely. But if it was simply about company, bg could have asked yj or th to go with him instead. And as you pointed out, he didn’t say the same thing to hnk, which means his request was directed at sb specifically. hnk didn’t seem to mind and stayed focused on the screen, like he already knew bg wasn’t asking him. hnk’s reaction here even reminded me of how someone might act when they’re caught in the middle of an argument between a couple. He just kept quiet, like he didn’t want to get involved. If we look at this situation through a purely platonic lens, bg’s persistence in wanting to leave with sb still feels unusual. It shows a level of attachment that seems beyond normal friendship, especially when you consider how often they’re already together.

It’s also kind of unreasonable to expect sb to give up playing the game just because bg wanted to leave. And if sb did leave, hnk wouldn’t have been able to play either, which could seem a bit inconsiderate. Most people, in that situation, if their friend said they wanted to stay back and play, would probably just accept it and leave on their own if they wanted to go rest. But bg playfully retaliated by threatening to mess with the power button. It’s almost like he couldn’t stand the idea of being separated from sb, even for a little while.

I’m sure sb would adore bg in any hairstyle 😩 He recognizes the unique charm that comes with both long and short hair. Long hair enhances the elegance of bg’s features, and I feel like it also influences his persona and attitude. He appears more graceful and sophisticated with long hair. And omg yes, sb used to love playing with bg’s hair when it was longer! I think he admires how well bg can pull off styles that he might not consider for himself, finding a certain satisfaction in seeing it on him.
That said, it’s undoubtedly clear that sb has a strong preference for bg’s short hair. He’s been very vocal about it, and when bg had gotten a haircut for the award show in Jakarta last year, sb literally couldn’t stop staring. He couldn’t hold back from complimenting bg, saying he “looked like his prime today,” which made bg so flustered that it left him speechless.
Since bg has such androgynous features, long hair can make him appear more feminine. I feel like that’s something hetero guys would find appealing because it aligns with their visual attraction to females. sb loves bg for who he is as a male. I think he feels that bg doesn't need long hair to be pretty and he actually seems to appreciate the boyish charm that short hair brings out in bg more.

I feel like bg wouldn’t have needed to recall the times in the past when sb mentioned that he really liked bg’s 943 hair (although sb’s said it enough times that bg would have always known this lol). We know that bg didn’t plan on dying his hair. He’d always say that he thinks he suits black hair the most, and even when he asked everyone around him whether they thought he looked better in black or bleached hair, 90% of them answered black. However, despite the landslide in votes and his lack of confidence in his bleached hair, he still went through with it. I think it’s very likely that it was largely because sb wanted it very badly.

Sb strongly advocated for bg to bleach his hair, and in the days leading up to bg’s final decision, sb repeatedly told bg that he thinks bg really suits bleached hair. Although sb didn’t share this himself, I’m almost certain he specified to bg exactly which style he wanted to see on him—that would have been the silver hair bg had during the 943 promotions. So, I think bg might have shared that sb was looking forward to his grey hair because he probably told this to bg recently.

Like, it’s no secret that sb liked bg’s 943 hair because he’s mentioned it numerous times, but one of the longest-running headcanons in the sgyvist community—and I mean for YEARS—is that sb doesn’t just think grey hair suits bg, but that he desperately wants to see bg’s dyed hair for his own enjoyment because that’s his type. And for bg to casually drop that this is actually canon… is kinda insane.

It’s perfectly normal and commonplace to compliment your friends like, “oh, this style suits you!” but it’s a completely different thing to nag them and look forward to them sporting your favorite styling on them. With friends, it’s not that big of a deal. I know for myself, I couldn’t care less how my friends dress or what color they dye their hair—it’s their body, not mine. As long as they take care of themselves in the bare minimum, I don’t have much interest. Of course, I have my own standards of aesthetics, so I might suggest to them what I think they look best in, but I don’t really care if they don’t listen, and neither do I get excited if they do lol.

Usually, it’s when you like someone and appreciate their beauty on a personal level that it benefits you for them to change their style to suit your tastes. It’s the psychology of, for instance, liking horn-rimmed glasses and leather jackets on guys, so you might gift those items to your boyfriend in hopes of seeing him wear it for your own visual satisfaction. That’s basically what sb is doing when he kept on suggesting and convincing bg to bleach his hair because that’s what’s most appealing to him. And bg knows this. He knows that if he changes his style to sb’s liking, he’s going to receive even more love from him—not that sb’s love is conditional, but bg knows it’s going to make sb extra happy, and naturally, he’d want to please him and look good for him.