Anyone who is "into" Socialist politics has a 90% chance of being too far gone into sectarianism and book worship. It's just how the world works. People with a highly developed ideology almost always have at least some parts that are wrong and will consider the most marginal culture-war issues to be complete dealbreakers for cooperation.
Stop caring about Leftists, they're more trouble than they're worth. Join the PSL. Work with real working-class movements in your city, and don't get dragged into the struggle sessions of your local DSA and Food Not Bombs chapter. Work with Arab groups, Jewish Voice for Peace, work with the libs who are opposing pollution and police violence. If you find an issue that speaks to people and organize around it, the people will come. Recruit from the people, not terminally online Leftists.
I'm not trying to say that they're bad people. I believe they're trying their best. But speaking from personal experience with our local organizing (of which I am just a very small part), other "Leftists" basically do not do anything that has any real effect. The DSA is a thinly veiled dating club, the CPUSA has terminal security culture brain, the Anarchists don't really do anything of their own volition because they have zero organization outside of polycules and rock bands. The only local group with anything close to the level of organization and professionalism as the PSL is the Palestinian Youth Movement.