Take that might cancel me some day, but there is no experience or struggle inclusive of all lesbians exclusive to all bi women so when people ask "why can't lesbians have lesbian only spaces" what I hear is "why can't we exclude people who share our struggles arbitrarily".
Maybe this is just because I'm in sapphic spaces and not mlm ones but I've never heard "Why can't gay men have spaces just for gay men, away from bi men?"
And frankly, to wish for the ability to enforce arbitrary distinctions ignoring material struggles and lived experiences with the sapphic community is an existential threat to me as a sapphic trans woman.
Like sure, maybe some bi women are het passing and her oppression is different from yours but there are bi women who have been with their partners for decades now and presented masc that whole time and I don't know what privileges you think they have?