This is true to an extent, but I find that reddit culture seeps its way into all subs. There is a overreaching lack of seriousness.
It's my observation that the average redditor is more interested in gaining upvotes via silly class-clown behavior, than actually contributing meaningful conversation. Or interested in upvoting silly comments.
Even in subreddits where the topic of discussion is something serious, such as a forum for advice seeking, people can't help but reply to posts with jokes.
What is worse is when people are downvoted for a reply which is intelligent and serious, but is contrary to popular opinion.