I've had quite the opposite experience in fact. You can find numerous topics on places like r/rust where people talk about the downsides of the language compared to others (for instance).
I think this is the big difference. The tone in comments about /r/rust is dramatically different than the tone in /r/programming. I often see some pretty crazy RIIR evangelism in /r/programming.
I don't know if this is a comment about rust the language or reddit commenters.
/r/programming (and all of the other major generic programming subreddits) generally just do not have good conversation (or at least have much more noise to signal), as a large percentage of the community is very inexperienced. Same thing goes for non-programming, high subscriber count communities. You eventually get a lot of people who think they are knowledgeable about a topic because they've read a lot of topics on the subreddit, but they're really just inexperienced people parroting the opinions of other inexperienced people.
