That's an interesting point I hadn't considered, but I still think this is different from the ideological purity fights that are common to every ideology.

Like, when we say AOC is a liberal or whatever it's an expression of disappointment that she's not as leftist as we'd like. But we're talking about positions she holds openly, we're not claiming she secretly doesn't care about free healthcare, or that it's a smokescreen for some nefarious purpose. The conservatives fuming about RINOs and the libertarians that booed Gary Johnson for being pro drivers' licenses (lmao) are operating on a similar principle I think.

The conspiratorial "they're saying they want good things but it's a trick to gain power and become evil tyrants" brainworms are very specific to communism I think. The closest thing on our side is when we accuse the reactionary right of knowingly trying to divide the working class by blaming everything wrong with capitalism on X minority, but even then I don't think they're "faking" it, necessarily. They really are bigoted and will do bigoted things if given power. It's not a trick.

Chuds do call everyone a Marxist though, that's true

we do this to other leftists too, it's approximately what opportunism means