[dude with glasses in a communist t-shirt, arguing] I'm the only leftist here, your opinions are TRASH
[dude holding a theory book on smug, arguing] Read theory you losers, you're all WRONG
[dude in an anarchist hoodie, arguing] Nuh-uh, I'm the only leftist here, you're SHITLIBS
[the three dudes are now caught in a cartoon fight, glasses gone flying, punches everywhere, while a firing squad of nazis are targeting them with rifles]
[a confused nazi asks] Why… why are they still arguing?
The antidote to infighting in my experience is organizing in ideologically diverse spaces. I've organized with liberals and all types of different leftists. It has left me with the perspective that all these people are good people that just want better for the world. It's hard to get angry at them once you know them. Per usual the solution is to touch grass.
You're right, BUT it will never happen. Hearing different perspectives and understanding other viewpoints will not only broaden your horizons, but it will also deradicalize you... but the people who you are asking to do this are the radicals who are allergic to ideologically diversity. Purity testing is one of the hallmark defining traits of the modern left, and the further left you go the more extreme it gets. The far left will excommunicate anybody who doesn't agree with on just about everything. You simply can't have a serious movement with this type of mentality being as prominent as it is.