>If the identithread devolves into who gets in the socialist clubhouse and who is bounced outside
That who is based entirely on whether or not sensible positions are held. Nobody is saying 'kick out the gays', the 'gay-ists' however, must go.
>feminism belongs outside of the leftist movement?
the word feminism can mean different things. there are certainly things called feminism that have no place in the left.
For ones thoughts to orient their worldview into contrasting groups which are not derived from productive relationship being the impetus for social change is idpol. These things are not allowed because they come from an incomparable perspective that will never be able to work congruently with the aims of the left. Even if they align from time to time they will diverge.
In some cases in the past the left has supported certain idpol based movements because it at that time aligned with the goals of the left. This does not make those movements of the left. This does not justify the ideological intermixing between the left at idpol.
You can not believe society is shaped by conflict between identity groups and be a leftist. Society is shaped by productive relationship, identities are formed by productive relationship. At best identity groups can help us analyze productive relationships better, but they provide no motive force.
The reason 'the left' always ends up a useless clusterfuck is because people think you CAN have this nonharmonious ideological soup, on the grounds of some shared interest. The moment things progress to something else the infighting breaks out because the fundamental perception of the world and how it works does not align. What is sensible, what is true, comes into conflict.
How can you expect people who see entirely alien causation to work together? This is not a differing idea of 'what to do?', this is not a differing idea of 'how to do it?', this is a differing idea of 'what is wrong?' on a very fundamental level.