You should try understanding where the other person is coming from before accusing them of being brainwashed by their government.

Have you ever looked at the so-called Political Compass? There's a 'left to right' axis and an 'authoritarian to libertarian' axis https://www.politicalcompass.org/ So you can be authoritarian and leftist according to them (there is a hidden bias in the test, towards libertarian socialism)

I'm not even saying that, I'm coming at this from more of a 'post-left anarchist' perspective, that there is no 'leftism' as such but what is left or right is a relative historical development, so otherwise contradictory movements end up being lumped together as 'leftists' by historical accident, but they still end up influencing each other, so for example marxism has historically influenced anarchism and vise versa.

You're saying there is some ahistorical 'true' leftism that's objective and indistinguishable from anarchism. You can also just say "anarchism is cool" and I would agree with you and we can not have this pointless argument. see also no true scotsman fallacy