[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?
Yep! Just having a fairly consistent and coherent understanding of the world is usually sufficient to get things more right than not, not everyone needs to be a grandmaster-level Marxist-Leninist with decades of reading and practice to view the world in a constructive way. Theory and practice is still necessary, but even liberals can acknowledge reality.