I do see what you are saying about an echo chamber vs a sub that engages in actual debate. When you are not in an echo chamber, it allows for discussion and a free flow of ideas. It also allows your opinion to be challenged and force you to see issues from another angle. However, there are also some subs that exist to allow for the camaraderie of a shared experience. As you pointed out on Reddit, r/actuallesbians was taken over by a lot of transwomen/supporters and banned anyone who didn’t agree with their belief that lesbians should fully embrace trans women as actual women. The mods over there strongly discouraged discussions about periods and other women’s issues, and would ban people who said they didn’t want to have sex with someone who still had a penis attached to them. The “refugees” from that sub made a new sub which was lost in The Great Ban Wave. Understandably, that sub on Saidit, doesn’t want to repeat history, so they made a rule that you have to be a female-born lesbian to participate in that sub. While that might sound like an echo chamber, there is still debate amongst the participants in that sub over issues that affect them. For instance, some users on that sub may support trans women 100% but disagree with TRAs violent bullying, while others may support a transperson’s right to transition but not their acceptance in women’s sports/prisons/shelters, whereas there are others who do not accept transwomen at all. From the outside, it may just look like they all just hate transwomen, but the topic is more nuanced than that because of their history and lived experiences as lesbians. Lesbians make up less than 2% of the population, and it is easy for their voices to get drowned out, especially in this current political climate. Also, since they are such a small group, it is nice to meet other women who may have a similar experiences as you, especially if you don’t know any other lesbians.