I sort of find myself in the same boat, but now I have very few high quality arguments.

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.