I like to keep in mind http://www.paulgraham.com/identity.html for these topics. And it does seem like there have been more and more of them--hopefully at worst it's a trend to "tech, programming, startups, and politics" rather than full generality. From that essay, the large number of comments on these threads is explained by "Politics, like religion, is a topic where there's no threshold of expertise for expressing an opinion. All you need is strong convictions." Though I would add that this extends to many more subjects, including bashing companies.

If submissions to nothing more than image macros ever get popular, then it's time to jump ship because HN has become way too much like Reddit.