It seems to me that there is really no feminist sub on Reddit where even a civil disagreement with feminism is tolerated.

Any dissent or disagreement with a feminist or feminist theory, no matter how polite, is grounds for instant banning.

I just cannot understand why a feminist would want to participate in twox, /r/feminism or /r/askfeminists knowing that you are in a non-critical echo chamber.

Pretty much every other feminist venue is extremely quick to ban any dissent.

If the only way your ideology can withstand criticism is by silencing the criticism, don't you really need to ask how solid your ideology really is?