it’s an ironic situation when homosexual women are seen as following the movement supporting political lesbianism for meeting the actual definition of lesbian.

Exactly this.

But as most old school radfems are gender critical in some way lines get blurred as you say, and radical feminism has received an upswing due to GC as some GC people do become radfems. People being banned from reddit and other platforms for not believing in sex change probably increases the radicalization.

Yup, that makes a lot of sense. Another ironic result of Reddit's (and other platforms') decision to ban people who hold different beliefs than them, rather than retain them on the platform and moderate them.

My guess is that the people swarming these threads are radfems themselves so they swarm these threads not because they are critical of gender but because they feel targeted as radfems.

That is my guess as well. Though I am skeptical as to the threat that a small 2k sub poses as opposed to the entire TQ+ movement...