i think sometimes minors don't realize that it's not their ass potentially in the fire on that one. and that boundaries are for everyone's health and safety, not just for theirs.
"i can handle it. i'm going to just tell them i'm 18 and follow anyway" is not as mired in power plays as the reverse, but it's still a real shitheel thing to do that i hope the internet as a whole has less and less tolerance for.
and honestly, one can only go "listen, my dude, if you're saying you need me to respect you and not follow you if you're also a kaomeda kin or like undertale or whatever, i don't understand why there's a problem with you respecting my request of 'don't follow me if you're a minor, because i could get assblasted to oblivion by your angry parents after they see me talk about dicks'. because legal assblasting is a bit more serious than you not liking fingers in his ass sunday, ok?" so many times.
of course, i may just be preemptively bitter on this point, coming from tumblr where despite locking my account down with every single tool available to me, saying 'read this before following', having my profile clearly state no minors etc, i was still having to swat away not only curious 15 year olds
but curious 15 year olds who loudly proclaimed that other 'do not follow if' lists needed to be respected, and insisted on their own 'do not follow if' lists being read and respected