When does a movement start to die?
There are a number of indicators.
One of the easy ones: when it loses the ability to tolerate internal criticism.
The principal actor here, Tlaloc, is a bit of a jerk. He's also an apparently bona-fide feminist, or at least feminist-friendly, male, with plenty of left-wing chops. In the course of a couple of long threads (you can dig around and find them if you want) he ends up getting into a pissing match with Feministe's new management and eventually is banned.
The main reason seems from here to be that Tlaloc believes the leadership of the feminist movement to be more interested in acquiring power for women than in restructuring society to be more equal. This is a problem that all ideology-based movements have - the desire to use organizational resources to accumulate wealth and/or power, rather than to move forward the agenda of the group. It can be forestalled, in my experience, only by being aware of the possibility, and frankly suspicious of movement leaders and prominent spokespeople. Which, in a movement as dispersed and decentralized as feminism is, means pretty much anyone who gets up on the soapbox and starts talking.
Tlaloc's case could certainly have been made with more diplomacy. But it's somewhat revelatory that the eventual reaction to his criticism isn't "you're wrong, and we've been discussing this for long enough, so we're finished" - but is instead "you're wrong, go away and never come back."