Hey homie, that does sound pretty frustrating.
If you're young, there may be some some legit parental concern wrapped up in there that's worth assuaging - he's seeing his kid rapidly change in ways he doesn't really understand, and he's heard vague stories about people getting "radicalized" online.
The bit about controlling your media consumption would really frustrate me, though.
It might be worthwhile to step back a bit from trying to directly argue points (because it's probably not going to change his mind anyway), and show that his concerns about you are unfounded through what you do.
You're not radicalized in some propaganda bubble - mainstream media shows the evils of capitalism & the ineffectuality of electoralism on a daily basis. You don't need a grayzone article to see that the Dems don't do what they say.
I don't know if that's helpful. I avoid arguing politics with my parents anymore (I'll just say something like "as a communist you know how I feel about that" and push past it). I don't have to depend on my parents now, though, so maybe that's different.