If they're smart, they'll try to avoid male collabs or talking about males at all. Not because males are inherently bad or anything dumb like that, but because it alienates a lot of your primarily male audience by drawing comparisons that don't need to happen. There's a lot of insecure people out there and they don't need to add to because it forces them to face those insecurities and NOBODY likes being forced to do anything. Keep that shit out of sight of your viewers to keep a suspension of disbelief. Filtering out insecurity might be smart in Tinder or the dating sphere, but as an entertainer, it's your job to keep fans happy.
The best approach I've seen for a male collab from a small corpo, is Amoria, who despite being mildly GFE, understood this and explained to her viewers that a male collab was to advance her career and gain experience as a voice actress (
>>49931274). She didn't assume everyone was ok with it, or made fun of her fans by ignoring their perspectives, she understood what I mentioned above and tried to acknowledge concerns even if she didn't intend to stop. While she might have lost true unicorns, she kept the reasonable fans around that will support you even though they dislike her acting buddy buddy with a dude.
Lottie is smart, she lurks /here/ and understands the lengths schizos (like me) will go to, to show our displeasure, even if she will ignore us. I hope the other girls learn from other corpos and avoid that sort of attention.
Is it unreasonable? No, plenty of other vtubers have done it before. Is it unfair? Also no, the people who watch them are mostly men. They can always choose another career unrelated to having a male audience.