(just as a heads up: i’m gonna be mentioning transphobic violence below.)
i’m gonna take a crack at answering you about beatrice’s views on love & lust.
so, first of all, i disagree with you that this isn’t really about men. i mean, yes, this is mainly about sayo’s own insecurities but those insecurities are rooted in real fears about the male gaze, patriarchal entitlement to women’s bodies, & threat of violence for gender non-conformity. also, yes, sayo fears women’s judgment too but women don’t have the same level of power that men do & i believe that sayo knows that.
consider this: if sayo was equally terrified of women & men’s judgment, then why doesn’t beatrice hate kanon as much as shannon? why doesn’t beatrice literally lose her mind ranting & raving about what disgusting filth kanon is too & that this love is meaningless without having sex & that jessica will surely hate him? george has his flaws but he doesn’t seem like a violent person, not any more than jessica is. & sure, beatrice also loathes kanon but you have to admit that the brunt of her hate is directed towards shannon. so, where is all this coming from? simply put: misogyny. i mean, every adult woman in umineko suffer so much because they’re told that women are only good for pleasing men & bearing children. & ‘pleasing men’ means, among other things, being ‘proper’ sexual objects. of course, kanon is also subject to abuse, stigma & oppression due to his “subhuman” body but there’s just a completely different dynamic between kanon/jessica & shannon/george. & umineko is upfront about the fact that the ushiromiyas really hate women & hold very conservative views on gender roles.
then, what does that mean if you’re a woman who can’t have ‘proper sex’ (meaning heterosexual notions of piv sex) with men? usually… it means intense violence, hate, & stigma. in real life, it’s a horrifying reality that in many places around the world, transgender women are killed at very high rates & experience a lot of domestic violence, abuse, & systematic oppression. &, generally, at the hands of men.
again, yes, this is mainly about sayo’s own self-hate & less about george but i’d argue that you can’t really understand where beatrice/sayo is coming from if you don’t also try to understand how sexism works. umineko is pretty good about how it talks about gender, sexism & transphobia; there’s a whole lot of layers in this scene of beatrice berating shannon than just sayo being insecure.