Well this is a debate about prescriptivism vs descriptivism, right?
No I don't think so.
You're arguing we should stick to the "intended" meaning. But at what point does denying the evolution of language to become more transphobic deny the genuine harms suffered by trans people?
I'm arguing that your particular claimed usage of feminism as a transphobic term (that is, the general inclusion of NBs as a class for whom feminism benefits is tantamount to gendering them female) simply doesn't hold up to scrutiny. This is distinct from the issue of women's spaces explicitly including NBs feels like misgendering (which is valid).
The premise of this community is fundamentally dependent on the idea that being a beneficiary of feminism MUST be entirely seperate from being gendered female.