There is an amazing book by S. Bear Bergman called Butch is a Noun. In it, there is an essay talking about what a butch is and what a butch is not. And I wish I had it in front of me because I would love to quote it. But you should find the book and read the essay. It is along the lines of, "A butch is X... unless ze is not."
"A butch is not X... unless ze is."
I keep thinking of this chapter when I'm reading tweets from @thelesbianmafia talking about how lesbians are not bisexuals.
I am about to give some of y'all head-explodey. Here it is: Did you know that there are lesbian-identified bisexuals? They exist. You might be thinking, "How can someone be bisexual and lesbian at the same time? That doesn't really make sense." Well, I'm not a bisexual lesbian, but in the interest of defending other members of my community, I want to say a few things about this issue.
First of all: There are essays in Bi Any Other Name and Getting Bi from lesbian-identified bisexuals/bisexual-identified lesbians (Protip: GO READ A BOOK. EDUCATE YOURSELF). Labels like lesbian and bisexual are, of course, related to orientation, but they are also related to political and community identity. @bivisibility said it well: "You can't be homosexual and bisexual by orientation. You can be lesbian by identity and bisexual by orientation." Some people feel more comfortable in lesbian communities. Some people develop a lesbian identity and then come out as bisexual, but don't want to give up their lesbian identity. Et cetera. I also know a pansexual lesbian who works at one of my alma maters. She is from the Bay Area and feels that those words best describe who she is - someone with a lesbian identity, but who is open to being involved with all genders. At first I dismissed her as ridiculous. Then I thought about it, and read other stories of women like her, and decided that it can make sense, and furthermore, it's not my place to judge what anyone wants to call themselves.
Those of us who are speaking in defense of bisexual lesbians are not trying to say that all lesbians are bisexuals. Apparently this needs clarifying, so let me say it again: We are not trying to say that all lesbians are bisexuals. Neither are we trying to attack lesbians, or trying to flog you with the P.C. whip (man, I hate the term P.C.). We are trying to tell you to pay attention, and to educate you a little. Here is where the Bergman chapter reference comes in. What we ARE saying is, lesbians are not bisexuals... unless they are.
Someone made the argument that this would never be said about gay men, but not only do I have a uterus, I'm a big ole feminazi, and I am going to call you on your b.s. Oh, and by the way, there are gay-identified bisexual men.
Suddenly I find myself defending my own personal labels. Like I should have to justify my argument with, I myself am not a bi-lesbian-whatever, but they exist. And that's exactly the problem with this argument. Why do you care so much what someone else calls themselves? Why do you have such a chip on your shoulder about what a lesbian is or is not? Do you really not understand the difference between lesbian as an orientation and lesbian as an identity? And who put you in charge of handing out the queer membership cards? The women who I have heard of who are bisexual-identified lesbians, etc. - do you have any clue who they are? I am sure that there must be such women from all walks of life, but truthfully, all the ones that I personally know of are older women who were there when this whole thing started going down in the 60s and 70s. They have fought in the feminist, lesbian, gay, bi, queer and trans rights movements for decades and decades so that they, YOU, we ALL, can be out and proud. Who do you think you are to question them? Respect your elders. You should not be mocking them, you should be thanking them and showing them your respect. A little history lesson for you.
I would also like to point out that (fact) human sexuality can be fluid, and (fact) behavior doesn't always match identity. There's a lot of obsession in the lesbian community with gold star lesbians, and (sadly) there is still a lot of biphobia in the lesbian community, and I have to wonder how much of this whole thing is related to those issues.
A better point is, why do you care so much what people call themselves? Choose whatever label you feel works for you (or don't label yourself at all) and go with it. Change it if you feel it's necessary. At the same time, let other people live how they want to live. Why bother wasting your time trying to tell people what they are or are not?