So... doing my best to speak from my own experience only, I just want to give an example of how identities are constructed categories and why it's not always sensible to assume that standardizing a definition clarifies things or makes them easier.
When I first came out and had contact with The Community, I was in my late teens and it was the early 1990s. So my language and my thinking came from people I considered experts, or at least more experienced, and that mainly meant people whose sense of themselves was forged post-Stonewall and in the heat of the AIDS crisis and, in situations where women predominated, through interaction (positive and negative) with second-wave feminism.
And I didn't have cause to analyze it at the time, because it was water to the fish, but the way we used terms about identity had everything to do at that time with one's commitment, if you will -- to say you were gay, to say you were a lesbian, to say you were here and queer, was perceived as a kind of pledge of loyalty, like a religious conversion. It meant that you were (even if you had to be closeted some of the time) removing yourself to whatever degree possible from the comfortable privileges of full participation in Straightlandia, and instead saying I don't belong with them, I'm coming with you now.
So in a way that I'm sure seems weird to people who never experienced it, there was really no interest in auditing someone's sexual history or the contents of their inner world in order to vet them. You could have slept with 700 men and married five of them, but if you said you were a lesbian now, you just kind of were, because that wasn't seen as a statement about your past, but about your future behavior. You had "changed teams," and everybody just kind of groked that and didn't question it.
I think when you understand that, it's easier to understand certain other things, like where a lot if intra-community biphobia comes from. Because self-identifying as bisexual was conflated with refusing to join the team, with lack of commitment. When your sexual identity isn't really built out of the sum of your thoughts and actions, but out of your promise to stay and share your life experiences with others like you -- insisting that you were bisexual (and I say this as someone who is! and did!) sounds like "idk, man, we'll see."
This expectation that belonging to the community meant surrendering Straightlandia, and that bisexuals were choosing not to choose, did help create the tight container of mutual aid that helped the queer community survive the rocky decades of learning how to exist visibly while half of us were actively dying, but it wasn't actually great for bisexual people, or at least for those of us who did feel committed and did want to be clear that we were in it for the long haul. It was tough to navigate with the language and the ideas we were given, and what very frequently happened is that we just kind of... got old enough to start pairing up, and we started using the language of whatever group we'd thrown in our future fortunes with.
So you'd have women who say they're straight, who think and feel straight, but if you get them talking, they'll tell you they dated women at one point, and actually their first heartbreak was this girl in high school, or whatever. But that's the past to them; it doesn't bear on what they see in their future, so it's not how they identify now. Or you have women who've been in lesbian relationships for ages, who are perceived by their neighbors and co-workers and family and friends as lesbians, who just kind of -- stopped relating to their younger bisexual selves and started perceiving themselves as gay. Because that's how we learned it, you know? Your queerness is about settling in where you belong, life-wise, and then that life forms your felt identity.
And now it's very different. Now the expectation is that you begin internally, by analyzing your subjective feelings, and you identify them: you feel this way sexually about women, this way romantically about men, this way about the genderfluid, all these infinite shades of perception and reaction. You locate the word that most accurately describes the shape of your experiences as a whole, and that's your identity, the thing you feel most like. And then that felt identity shapes whether or not you belong to the community, whether you "get to" go to Pride or whatever (I assure you, in the 90s it never occurred to us that straight people would perceive attending Pride events as a treat we were withholding from them).
(By the way, I'm framing this as generational because I think it is to some degree, but there's no such thing as a monoculture, and even in the US, which is what I'm describing, there are still parts of the community, particularly in conservative locations and I think particularly in mostly male communities, where the dominant understanding of identity still is this "older" model of loyalty-first, of disinterest in the details of your past so long as you have your teammates' backs.)
And I think -- on balance, it's an improvement. Letting people just be bisexual their whole lives long is way better for a lot of reasons, and has additionally been good for the community -- it might challenge some people to relate to the heterosexually-paired as Teammates, but keeping the energy and wisdom of people who were once expected to retire their gay gun and badge has added to our numbers and diversity.
It does mean that there's a certain culture now of trying to force people to match their experiences to The Correct Definitions, and I notice a depressing number of people questioning others, or even worse themselves, over whether they really qualify as X based on things they've said or done before. That looks ugly to me, and it makes me long for the days of being able to say, whatever, the past is the past, let them focus on who they're going to be going forward.
But then, our pasts really don't disappear, and I don't miss back when people were kind of expected to pretend that the person they were and the people they loved at 24 stop counting for anything at some point. Life is complicated, life is a flow of constant changes, but we should get to keep our pasts. They're ours. And of course, even if you've never loved anyone at all, you can experience your mind and heart as queer (or as whatever other word feels good to you) -- I think that's a powerful insight that would have been entirely alien to me 25 years ago, but it's true.
Anyway, I think what I'm saying is that life is not an infographic, and people fit words to their life stories not according to strict and objective dictionary definitions, but based on social and ideological factors that construct the categories we move inside. And people who use words in ways that don't make sense to you are maybe coming from a whole worldview that's opaque to you, and maybe learning who they are is key.
(This is not a post about why it's okay to say that Eliot Waugh is gay even though he's been known to enjoy sex with women, but it could be? Like, if that's what you get out of it, you're not wrong.)