This has been explored on other threads and maybe we need a sort of history archive.
It was any issue back in the 70s, but in the euphoria of Women's Liberation when things seemed(!) to be moving towards women's autonomous rights, I dont think anyone thought trans identity would be anything other than a very small group.
But what we didn't take into account was the politicisation of trans issues by queer politics. This in fact is what started the trend (deliberate strategy) to erase the word sex and substitute gender. By erasing women as a biological reality and instead saying it was gender, a choice, men could no longer be accused of being the sex class oppressor of women, because sex no longer mattered.
Women's Studies became Gender Studies, and 2 or even 3 generations of students were educated (brainwashed) into the thought process of gender identity and individual rights over collective rights. These students then moved into the media, politics, education - and campaign groups. (The editor of the Guardian says queer politics informs every decision she takes.)
When Women's Liberation fell apart after the National Conference in Birmingham the grassroots networking and sharing of information and joint campaigning also stopped. But queer activism didn't.
Queer activists actively practiced entryism into areas of influence. The real power isn't the networks that are named and seen. They are the private networks, in much the same way that Men's Clubs probablly had more power than Parliament.
Fast forward a few years / decades and you get the culmination of this lobbying resulting in the GRA. And this is the lynch pin that has undermined women's rights. Because even though everyone knows it isn't actually possible, you could get a certificate to say you had changed your sex.
So while we (women) were all asleep or still nursing our grudges since Birmingham trans activists, actively supported by MRAs were infiltrating everywhere. Reallly important to remember how convenient the trans arguement is for MRAs.
One veryimportant tool for them was language. Newspaper no longer reported someone's sex but their gender. Prostitutes became "sex workers". The later woke rainbow haired militants are effectively the grandchildren of those early queer activists.
Not being rude but mumsnet was quite late to the growing catastrophe. But, not just because of the individual input, it because one of the few, or possibly only place where women could openly discuss the threat to women as a sex class by the GRA. So that when the consultation was announced (with MPs and queer activists convinced they would get self identity enshrined and sex deleted as a protected characteristic) MN FWR was hugely important in creating the groundswell against what was about to happen.
And since then, amazed that anyone had not fallen for their analysis the whole trolling, threatening, silencing, banning, of gender critical politics started an all out war on women. And because they were so well entrenched by now in so many places of influence, there basically was only mumsnet providing a platform for women.
So this isn't just about the influence of Stonewall who as an organisation have grown because of the pervading influence of queer politics ie why would they (apart from the money) change an organisation created to protect people who were same sex attracted suddenly start campaigning for people who said sex wasn't real.
If you have the time listen to Selina Todd talk about how queer politics spread its tenticles and created the ground work for trans activists.
As someone said at the time it was ironic that a socialist feminist historian was confirming 40 years later what radical feminists were saying / warning at the time it started. ie Janice Raymond.