Bisexuality is defined by attraction to both one's sex and the opposite sex, though. It doesn't involve gender (an oppressive social construct!) and even less "more than two", as there isn't more than two sexes in humans. Your argument both ignores the cultural implications of gender (see above) and biology... you mean well, but what does "identifying as a woman" even mean? what is a woman?
That’s an outdated definition of bisexuality. Here are some modern ones:
Aside from that, the rest of your message is transphobic - complete with “only two sexes” and ignoring intersex people, “ignoring biology” as a way of promoting gender essentialism, and rhetorically questioning the validity of gender in an attempt to delegitimize trans, non-binary, and genderfluid people.
This is TERF rhetoric. Do not contact me again.