Hi there anon!! I'm sitting down now because I have a lot of thoughts about this and I hope I can convey them in a bit of a comprehensible way.

First of all, I don't think this should be blamed on shippers. Someone's (internalized) homophobia can't be blamed on someone outside of the person themselves. For example with the 5th harmony example: even if the two you're talking about weren't shipped at all, the queer person would very likely still feel the same guilt/burden. It can be due to shippers that this person discovers "Hey, I might be queer, because I like the idea these fans have" but that's not a bad thing, right? Even without shippers, this person would most likely figure it out sooner or later.

The biggest point, I think, is that especially with celebrities who cannot realistically come out of the closet to fans, we CANNOT know their sexuality. We don't know if they are queer or straight for sure.
Yes, you can sort of see signs, but since they cannot come out, it's of no use arguing about "oh but What If they're straight and you're making them uncomfortable" or "oh but What If they're queer and you're making them feel guilty because What If the person you're shipping them with is not queer?"
Shipping is and will always supposed to be separate from the people you're shipping---meaning, you shouldn't make any assumptions directly to that person regarding your shipping. Saying two people look cute together is harmless, asking them if they're dating is A Whole Other thing and is not appropriate, no matter if you're shipping them or not.

Every celebrity has different struggles and different relationships with themselves, the fans, their sexuality, etc, so you gotta look at what's appropriate and what's not case by case, but 99% of people who ship real people do Not do it in direct relation to those people, they just make up little scenarios on the internet, which is harmless.

Kpop idols are very aware of shipping culture because it has always been a big part of idol culture, at least since the second generation. And it's been a big thing in countries like Japan and Thailand too, so believe me when I say that making a comparison to Western artists is not quite valid here. There's a culture difference.
Again, it's a case by case thing. Of course there are idols who don't appreciate it, but again, there's no harm in keeping your imagines away from them.

But to circle back to your specific question about making people feel predatory: I believe shippers cannot do that, and especially in kpop, where the idols cannot come out and shipping is a thing they're all aware of, it's not a problem that we should be worrying about.
We don't know if any of the idols are queer or not, and even if we did, it's mostly the person themselves and their relationship to their queerness/their internalized homophobia that's the problem, not an outside factor, and it's for the person themselves (and perhaps also the groupmate who they feel predatory towards) to solve this or work through this.

(Another tiny little thing I want to add is that this thing about queer attraction being seen as predatory, and thus queer people feeling guilty for their queer attraction, is a society issue, and is part of (internalized) homophobia!! It's been around for a long long time, long before shipping became bigger in the western rpf sense)

OOF okay that was long but I hope this makes sense, thank you for coming here with this question!!