the sheer number of relatively level-headed vtubers who willingly hang out with her makes me think there's something they know that we don't.
This is the only part of your post I strongly and passionately disagree with. Most vtubers are clueless of anything but their immediate surroundings and never investigate anyone they interact with beyond the surface level. They are not men, and they are
especially not demented autistic men like us who obsessively dig into the pasts of everyone we take interest in with pseudo-voyeuristic glee. There are some who do, but they do it because they've been brutally mistreated and prosecuted so many times they've developed that skill as a defence mechanism.
Beyond that, these are zoomers; late teenagers to early 20-somethings, with Hexa being by far the oldest in the group, and I don't need to think I need comment on
her judge of character. You are ascribing a level of world-weary suspicion and calculating analysis to people who simply don't possess it.
Edit: Oh, and to clarify further, this is direct personal experience. Half of my contacts with vtubers involves patiently explaining to them that they should
not earnestly spill their souls to a new collab partner just because they thought their model was cute, or mod random people who sounded nice in their Discord, or to avoid transparently obvious predators.
You have no idea how bad things are when a woman wanders blithely into the lion's den with such carefree innocence that the lions themselves feel the need to politely explain where she is and that she should leave and come back when she's more experienced, rather than do what comes natural to them and simply devour her on the spot. For every rightfully-paranoid Kirsche, there are fifty vtubers who would fall for the Bonzai Buddy copypasta.