I don't know if HN was always like this and we have more political links on here recently, or if it's a change in membership composition, but from what I can tell the range of allowed opinion in political discussion has greatly narrowed over the past six months or so compared to that in technical discussion. And that's too bad.
It's about how you say it, not what you say. Also, you can't particularly be upset if the vast majority of startup founders are super pro capitalism; this is sorta ground zero for all of that, eh?
If I say, "4chan FTW, lulz!", I will get downvoted, and rightly so. Compare:
"I think a lot of people on HN tend to dismiss 4chan as juvenile and immature without giving due regard to its tremendous creative potential and brand recognition. Just look at the Cheezburger Network, a multimillion dollar company whose sole business model is to recycle 4chan memes. Additionally, it would be hard to name a site as seemingly pointless as 4chan that enjoys its popularity or notoriety. Even Someething Awful, which arguably did what 4chan does, but better, never enjoyed the number of users or visibility that 4chan does. It's clear they're doing something right, even if they manage to piss just about everyone off."
Now I've presented a contrarian opinion in a way that presents a clear argument for why I hold it. These types of posts are far more palatable to people who, really, are just looking for interesting things to think about.