Where does the bisexual women only date men come from?

This is a rhetorical question. I'm aware of where this rhetoric comes from. Biphobic queer people love to say this so they can further their biphobic belief that bisexuals are "basically heterosexuals" and use us as a punching bag guilt free even though they have been proven wrong in their belief. Also bisexual women in relationship with men tend to be louder about their bisexuality comparingly to bi women in relationship with women, which I understand. Bi women with men always have their queerness erased so they are louder about it. I just wish bi women in relationship with women also were loud about their bisexuality. It also doesn't help that queer people immediately assume all sapphics are lesbians 😑 it's just frustrating that our bisexuality is erased. Bisexuals need to be loud and proud about their identity like other queers