Obligatory 'why not both' answer.
That said, there's a difference between the rationalist culture and the sterile textbook definition rats tend to tote around. Rationality as suspicion of your own thoughts is a subset of rationality as a culture, i.e. the culture endorses this practice.
But beyond that humility rationality bifurcates into several different strands. Not everyone trolls blogrolls into the wee hours of the morning and jerks themselves raw over the size of their rss feeds. I think those people are missing out, but who gives a shit.
All things considered, HlynkaCG is faggot. /ratanon/ isn't LW and it's not SSC. It's for people who've already strapped themselves onto Big Yud's wild ride to shitpost and write kinky fanfiction.
But no wait, rationality is srs bsns guise.