because i can block whoever i want ❤ as can they, and in my experience posting and laughing about it often ends up with people going to the account and harassing the person in question. I've had more than one close friend near run out of fandoms thanks to the dogpiling resulting from tweets like that, so yes i do think it's being an ass. a block is a pretty clear sign someone wants nothing to do with you and it serves both sides in this case, just block back since you clearly aren't going to want to see each other on the tl and go about your life. when someone blocks me i manage to mind my own business and move on just fine!