. You’re unprincipled, ignorant, and close minded, and selfish

these are just insults or ad hominem.

no mentally stable person would hold such a view.

prove this

Don’t make me laugh.

literally an appeal to ridicule, not a refutation.

You don’t care about the hundreds of millions it has oppressed or killed

it hasn't done that.

It's clear from your post history what sort of person you are. You don't respect anyone who is outside of your norm. You're hypocritical; you claim your view of the far left as the only valid one much like you criticize others for doing with veganism; you engage in black and white team politics, seeing those with a certain label you get to apply at a whim as inherently enemies like you accuse the faceless mob of "reddit users" of doing. You don't care about reality or decency. You care about winning.

Marxism is authoritarian,

for definitions of authoritarian that are the same as "egalitarian"

oppressive,

to oppressors

violent, hateful, extreme

you're just lying now

and is a complete failure.

except all the times it's succeeded