It's amazing what original thought can do for a person. That little button has more power than most people think.
Keep in mind, that you're posting that on a different social network (with different rules, but still - social network), that also has exactly the same system, with upvoting.
Reddit and Facebook and Twitter are chalk full of people ready to have a low quality debate, but there are some rare instances where you'll get some genuine insight from interlocutors.
HN seems to be a good source, but in general on any given subject it's very difficult to find a good faith, intellectually honest, substance-based disagreement on the Internet.
As you say, it seems better for one's IQ and eIQ to lose Reddit and Facebook and Twitter, but it'd still be nice to have a place to sanity-check new ideas.
But, I did have a tendency to get into arguments on forums of other sites, including YouTube of all places. Most were news/political sites, though. I stopped commenting on any sites other than this one for many of the same reasons. It's just not worth it and is a giant time suck to comment elsewhere. I absolutely love not seeing asinine responses to my comments where I get enraged and then feel obligated to respond to counter that idiocy. I hated that feeling but was obsessed with proving myself. I do not miss that at all whatsoever.