I think the TWAW thing is the crux of the matter.
Most of the GC feminists on this board (not all, but most I would say) go along with the spirit of the original GRA, which is that a GRC gives a trans person the right to be treated as if they were a member of the opposite sex, except for a small range of circumstances in which biology (or our social rules around biology) matters. So, reasonable exclusions would include women's prisons, women's homeless shelters, women's sports, women's open-plan, communal changing rooms.
The current range of transactivists want to be treated as women in all circumumstances. Including prisons, sports, homeless shelters, communal changing rooms.
However, they don't want to say this openly. So they talk about discrimination and harassment (which is wrong, and everyone would agree it was wrong, but isn't actually the point, because gender reassignment is already a protected characteristic, so transphobic attacks can be treated as transphobic, with the extra sentencing such crimes carry, which is as much as the law does for any of us, and more than it does for women, because misogynist attacks don't count as hate crimes). Then they twist it to make it look as though GC feminists are against trans people having protection from harassment and discrimination, which is a lie.
But what's really at issue are the practical consequences - do women get to say no to transwomen in women's prisons, homeless shelters, communal changing facilities, sports, or do they not get to say no?