FWIW, I've been feeling like the comments on HN have been more negative and combative than usual over the last month or so, too. (I've been a HN user for about 5 years, too). I've not been quite sure why - there just suddenly seems to have been a bit of a tidal wave of snark.
It may be seasonal, or something similar, and I'll admit to having anecdotal evidence only, but I have had a similar impression to the OP, albeit not quite as strongly.
I wonder if some of it is defensiveness from users scared HN will turn into Reddit? Certainly, I've seen a lot of "downvote this post, it's not something that should be on HN" comments lately.
It may be seasonal, or something similar, and I'll admit to having anecdotal evidence only, but I have had a similar impression to the OP, albeit not quite as strongly.
I wonder if some of it is defensiveness from users scared HN will turn into Reddit? Certainly, I've seen a lot of "downvote this post, it's not something that should be on HN" comments lately.