Lesbians and gender have a long history together, hell, the fundamental lesbian text Stone Butch Blues and one of the fundamental historical trans books Beyond Pink Or Blue are written by the same person, Leslie Feinberg, an icon of both communities simultaneously. Zie put a coherent voice on something that was pretty common in the community at the time, the idea that being gay (especially as a woman) inherently comes with an element of gender nonconformity.

We live in a misogynistic society that almost entirely defined women around the concept of men, and, more importantly, around facilitating hetrosexual relationships (and the exploitation of free domestic and reproductive labour within those relationships) with men - look up any definition of feminity/womanhood, and you'll see: nuturing will be on there, something about being naturally cleanly or caring or empathetic, quiet, invested in physical appearance - almost every trait listed will be "useful" to men in some way. This type of shit. As much as people might be trying to change that idea now, it was absolutely the norm for fucking centuries.

So what is a woman when they can't fulfil that societally designated function? For a while, it was an idea amongst homophobes that lesbians, especially butches, weren't real women. Or that we were women 'wrong'. They didn't like it at all when some of us were like "yeah sure maybe lmao" (although, of course, for slightly different reasons). Hence non-binary, transmasc, and they/them/he/him/neopronoun/whatever lesbians being suprisingly common.

To steal a blogpost that always Hit for me:

I’m very uncomfortable with being called non-binary because my standard answer to “what’s your gender” is lesbian/butch and my pronouns are he/him. I respect NB lesbians but I’m not NB. I’m not trans. I’m not cis either. I inhabit a bizarre space, a corner into which I was backed by the heteropatriarchy, and ideally this space should not exist at all. Naming it legitimizes it. It’s not normal that so many lesbians feel alienated from womanhood and feel that they can’t exist as women because of who they are. I know that if breasts weren’t considered almost only as loci of male pleasure in our culture I probably wouldn’t be dysphoric about them. I know that the reasons I can’t call myself “woman” without flinching are all linked to the violence the heteropatriarchy has enacted upon me since I was born and to the trauma of growing up as a butch in a world that hated me. I was psychologically mutilated; why would I want a name for this? Most importantly, why would I insult NB lesbians by acting like their identity is in any way comparable to the way I feel about womanhood? A non-binary lesbian has a concrete gender identity that they can usually name or at least describe; I just have a gaping hole where people reached in and tore out something I will never get back. It’s immensely different.

Feeling alienated from your (supposed) gender when that gender has been/is used as a vehicle for oppression, objectification, and demands of hetrosexuality is pretty goddamn normal, regardless of whether or not you actually are that gender (ngl it makes it pretty hard to tell if you're a different gender, or just reasonably uncomfortable with uncomfortable shit). Why shouldn't i express that alienation and discomfort with gender/feminitiy/womanhood?

When a friend refers to me with he/him irl, they do it in the full knowledge that i'm not a man, and i'm fairly sure that anyone else in real life who overhears or assumes those pronouns does so knowing that, whatever the fuck i may be, i'm certainly not cishet, which is enough for me. Large swathes of my life only make sense given the context of being a butch/gnc lesbian; being noticeably non-cishet is important to me because, for better or for worse, it has informed so much of who i am and where i wound up - i don't think i'd be the same person (and i absolutely wouldn't be in the same situation in life) otherwise. I am transgressive of people's ideas of gender just by existing, and that, at this point, is something i've come to like, its a solid 'fuck you' as far as i'm concerned. Why not lean into that if it feels right?

TL;DR

There's no pronoun for "Lesbian, But Honestly At This Point My Relationship With Women Is The Only Reason I Might Ever Class Myself As A Woman", or "I Don't Know, But I've Dealt With Enough Misogynistic Bullshit That 'She/her' Grates On My Ears Now".

Basically, you might know you're not a man but not know for sure what you are, or even just like different pronouns - tbh i have no idea if i'm non-binary or maybe somewhat trans-masc, i don't know, and quite honestly i don't fucking care. I know i like he/him, but don't want to step on the toes of transmen or non-binary people, so i personally use hy/hym instead, but i do 100% get he/him lesbians and would join them if i could get away with it. (Hy/hym, to me, essentially means he/him* where that asterix leads to "*but not a binary man". And that'll do for now.)

even more TL;DR:

Pronouns do not equal gender, you can use whatever pronouns you like and still be a woman/woman aligned (in the same way that you can look/behave/feel/etc however you like and still be a woman), and some people just perfer masc pronouns. For me it relates to the traumatic effects of Society™ and a lifetime of misogyny and objectification, but it might not for all of us.