The year was indeed 2015, and his political content would fit OP's description, but the reason for the ban was that he was repeatedly being a total asshole, not "YC is scared of anti-fascists".
Also, whenever the question "where are the tech unions at," comes up ,its because the system crushes anyone who is slightly left leaning in this regard.
Excerpt:
You’d be one of the best people they’ve seen in years, and unlike the people around them, you’re honest and ethical. The thing that’s holding you back is… a reputation problem. People Google you and think, “This guy’s going to start a union.”
This is going to make it hard to place you. Guys like [name] don’t like people they can’t buy. If I were you, I’d start blogging again and come out against unions. Do that for six months, and I can put you anywhere you want to go.
Huh, I'm looking around at my large house, wonderful life I've provided for my family, nice car, fun job, sure doesn't seem like a scam.
I've noticed that people who have failed a lot or things aren't going well like to blame external factors, and often reach for simpler ones.
Is it perfect? no. Is it better than everything else because of Capitalism? Yup...
In some scenarios capitalism can work really, really well. but lose a job, have a health issue and you then see that it is just a house of cards that generally works for small fraction of the population. not that other systems don’t have their own issues (and more) but capitalism is always good in the eyes of the beholder and over time there are less and less happy stories (USA is perfect example, see graphs of income inequality/gaps over time…)