What with having late-transitioning male colleagues in the workplace, and facing a 'big-boned' transwoman in an amateur golf competition in my leisure time, I must have been a glutton for punishment because I joined the Green Party.
Members submit policy motions, which are debated online, redrafted and then put to a Conference for a further debate and vote. As the years went by, there was a spike of motions coming from Aimee Challoner, LGBT and the Young Greens on transgender rights.
The Manifesto for Women was renamed the Gender Equality Manifesto. There had been a 'find and replace' makeover to remove the word 'woman' in favour of 'people' - except when talking about migrants and women in Third World Countries. Discussion in the members' forum turned nasty as beardy blokes told dissenters to shut the feck up and take their transphobia elsewhere.
The Party, to this day, states that transwomen are women and form part of the 'non-men' group. The Greens have a shameful history (like the Labour Party) of disciplining, suspending, smearing and piling-on non-believers: a foretaste of the worst kind of Trans activism.
When a political party aggressively pursues men's rights at the expense of women, it's time to leave and look for allies left, right, centre or apolitical.