They're in a corpo whose business model is based on and explicitly involves making money off the mentally ill, volatile people (among others). Antagonising that particular source of money may be better in the long run but it's bad business and also carries a risk of getting other talents caught in a backlash.
I feel it should also be said that unicorns on the Western side are mostly tame in comparison to the native JP ones - with majority of drama coming from rare schizos and mostly from bored shit-stirrers - and talents do not necessarily uphold the "idol" ethos very hard, but taking a dump on a group of viewers is an escalation that could, depending on harshness, cause other filthy paypigsvalued paying customers to reevaluate their own worth in the eyes of the talent: you've come to a realisation that your oshi doesn't love-love her viewers unequivocally and thinks some of them are scum BUT THEN you also come to a realisation that you're just a tiny little bit attached to her and think of her as your friend? But we're not friends and she thinks people with too much attachment are garbage, maybe it's time to move on... etc. Point is, it's carrying risks and negatives going beyond just making some enemies, certain illusions need to stay intact for the business to carry on as it did before no matter the ethics and whether maintaining it will cause the talent some headache.
