The political subreddits are mostly echo chambers of a single party that has taken over there especially in "nonpartisan" groups, especially in news subreddits like politics, news, and worldnews. Even moderates aren't really welcome and I've seen anyone who said something even slightly conservative get ripped to shreds and moderators are like "I'll allow it", pretty crazy. There are many, many good informational forums though, like the article mentioned you just have to look out for marketeers and snake oil a bit.

Its not even as open as a single party right now. Its single candidate.

/r/moderatepolitics is my new /r/politics.

> Always investigate who is behind a statement that advises you one way or another.

What would you do here, specifically?

If you are implying that it can be difficult to investigate a particular person like, say, a reddit mod with very little biographical information and no particular post history, then I'd suggest that finding that someone giving advice is not themselves investigatable is itself an answer. Yeah, that metric will have false positives, but, alas, fewer and fewer over time as a site grows.