Mori is a cunt and should graduate, no doubt. But only because of associating with anituber fuckers and not maintaining her kayfabe and bringing irl shit into vtubing like a twitch thot. Not because of males in general.
NO ONE fucking cares about male collabs, drill into your thick skulls fucking newfags. Suisei and Sora collabed with males and no one fucking cared because idolshit is not about unicornfagging at all, it's about you supporting your oshi's dream in getting better at singing, dancing, creating content, reaching milestones and celebrating occasions with her fans, achieving her goals. Even for vtubers who do GFE only the most deranged but wealthy minority unironically and literally considers them their girlfriends. They are the reason some girls choose to explicitly say they'll never collab with males, they are just shielding themselves from schizos, it's not like they run away from any male in a kilometer radius in public, kek. Other people in fanbase can have their reasons - finding a chuuba sexually attractive, liking her voice, liking a specific type of her content, finding her funny etc.
But the supreme form of supporting a chuuba is making her your idol, your kamioshi - not as in unicornfagging, but as in smiling every day seeing her tweets and streams and supporting every single one of her dreams. People who are saying things like "I watch my oshi for games, I don't care about her idolshit, I hate jpop" etc deserve the rope. It's not only about singing and performing, it's about deeply caring for a person and wishing them happiness and success no matter what and feeling happy from smallest things they do. I think it's even weird to have sexual thoughts about your kamioshi, I find a lot of vtubers sexy but I can't bring myself to enjoy my oshi's doujins, they all are way too low quality and ugly for such a beautiful girl. Truly supporting your oshi is a bit like a religion though much less extreme and harmful, not like a fucking relationship you dumbfucks. If she's truly your oshi you just admire her forever, you don't think you'll be deserving of her someday.
And yeah, as a postscriptum - people are fine being friends with opposite sex if they're not mentally ill or extremely socially stunted. I've never even really seen people who would have a problem with it irl. Not all people are scumbags, a lot of them are actually capable of maintaining a happy relationship and having friends of opposite sex and not thinking of fucking them.
And then again, the problem with Mori is not having a male friend but being a lying cunt and uncaring entitled bitch and not trying to maintain a vtuber persona, like people already said.