AIBU to consider leaving our knitting group over its new policy?

Yep. We're all wasting our time here.
OP doesn't know what she wants, other than a life without left wing opinions and trans women.

This bears repeating

I've just caught up on this thread and don't think I've ever seen such a 'problem' that's perfectly made for a Mumsnet discussion.

In the very first post she says I don't want men in the group
It couldn't be clearer

I think you're perhaps being a little disingenous in your OP, you start by saying you don't understand what people mean by non-binary, and imply that you think not wearing nail varnish could qualify, then use the terminology of the online debates on this quite fluently a few lines later (TERF).

"...Apart from the fact that I don’t know what non-binary people are other than people who don’t sign up to gender stereotypes (most of the women currently in the group don’t go in for nails / make up / fake tan etc anyway so what’s the difference?) ....I have no desire to ‘out’ myself as a ‘TERF’ by complaining .... I just disagree wholeheartedly with the idea that men should be treated as women because they say so."

I think you had pretty strong views on this before the new(ish) leadership proposed being welcoming and friendly to all, and you're portraying yourself as an uncomfortable elderly newcomer to the debate, to gather sympathy.

Maybe start your own, womens only knitting club, with that aspect made clear as part of its identity, if you feel so strongly about it; its not your job to ensure the existing club excludes people to your personal agenda.

I think she does - it's trans women as a whole she has a problem with.
Not men who aren't trans, as she said it'd be fine if it opened up to be a mixed sex group.

Is the chair willing to set it to a vote?
Thats the only fair way decide amongst the group.
If the voting doesn't support her ethos then you're okay to continue, but if not you are, and have always been, free to leave.
BTW, I wouldn't choose to stay in a mixed group that had previously been female only, trans or otherwise.

Maybe someone trans actually joins but they turn out to be nice? You never know. Not all trans people are raving misogynistic loons (and I'm as TERF as they can be).

But not every trans person is radical. That's a dreadful generalisation. Again, both the trans people I know just get on with their lives quietly.

YABU for your weird contradictory views, your stereotyping of men, and you wanting to hear others views but not if they’re left-wing.

If you said in your post you don't want men in the group. Then a reader will assume you don't want men in the group. Now you say you don't mind men joining. Which is it. Personally I think it's a fuss about nothing as no trans folk have even asked to join. Or men either.

She doesn't want to exclude men, she wants to exclude men pretending to be women

OP, I would just push back on the idea that you need to 'recruit' anybody. It sounds like it is a pretty successful venture as it is.

You should also push back on the idea that it is virtuous for trans and non-binary people to be doing a female-coded hobby too. Do you have a DEI statement? I don't think you need one but if so, what does it say about race, socioeconomic class and disability?

FWIW I have done knitting groups and they attracted very few men. The men who did come along were quite fun older gay men, with the occassional younger bear, who were also quite sweet.

I would wait and see if anyone male actually joins and what happens then.

So if you're "wanting to avoid the male gaze"
Why would you be fine if the group changed to men only?
You're contradicting yourself all over the place.
As well as trying to gaslight people by pretending there's something wrong with their reading comprehension.

I think it is very weird to have that as an agenda. If they approach the group and wish to join, then fine.. that’s one thing. Specifically trying to target these groups - without consulting with the existing members is risky.

So the issue here is that for you - and it seems a few others - it was specifically established as a ‘WOMEN’s knitting group’, rather than just ‘a knitting group’. The single sex nature of it was core to its foundation.

The new chairperson does not share this vision of the group. It’s not unlike the WI situation where members now need to discuss whether they wish it to remain single sex or be trans inclusive.

As others have said, and if you are certain there are several of you who feel this way, you [all] need to speak up. You need to say that for personal reasons you do not wish to expand the membership of the group you co-founded to be a space for purely women to bond over a mutual hobby. You need to ask for a secret member’s vote to ascertain what everyone else wants. If the vote opts to include trans women [after all, its not non-binary biological women you have an issue with], then several of you may have no choice but to leave (and set up a new group).

Someone needs to explain to the chair that if the group lets trans identifying men in then they have to let all men in under the Supreme Court ruling. Is that what they want?

Actually, that’s an incredibly minimising post. A principle of women’s only spaces not being forced to include men is incredibly important. It just so happens we as that on a practical basis this particular thing might not be affected. You could swing it the other way. If the numbers are so small why bother with trying to change the group and make it trans inclusive? What’s the point in that? Are you suggesting the reason the person trying to change the situation is also ND.

That's not what the very first post says though. Read it again. She's no idea what she wants.

She doesn't mind men joining.

Just speak up and say no to men joining.

My women’s sewing group meets in the local library (no charge for using the room) and we’ve discussed this previously and agreed no men, however they identify.

If they’re acting like hand maidens, leave and set up a new group on a different day but keep it informal. That’s where you went wrong IMO.

Presumably the same reason that men want space away from women, on male-only golf courses and shooting clubs.

Women fought for the right to be able to fully participate in traditionally male pursuits. And now we're regressing back to, yes but the women should be able to knit without men, and the men should be able to play golf without the women.

There are legitimate concerns around places where women are vulnerable, either physically or emotionally.

A knitting group - OP needs to grow the fuck up OR set up a women's-only knitting group that excludes men AND trans people, so she can talk about womanly things. That's fine. But knitting groups as a class don't need to change because she's a terf.

Let's stop being so divisive. Women's rights, men's rights and trans rights can easily co-exist if we all just stop being dicks.

You've said you don't mind men joining. Your narrative is all over the shop.

So should a white person have been allowed to black up and demand access to a black space and force everyone to pretend hes not just black, but the most oppressed, vulnerable type of black person?

That would be the equivalent here.