Perhaps, but that would be unfortunate. When I get together with my friends, we can discuss whatever we want without needing to worry that the very choice of topic might lead to the group being diluted and eventually poisoned.

Personally I am not convinced what happened to Reddit and Slashdot etc would happen here anyway. It is quite possible that Reddit has accomodated all the people who wanted a current-style Reddit and they are all happy where they are. There is a finite number of people, after all, despite how it sometimes seems.

The people arguing against political topics here, based upon the experience at Reddit, do so referring to a single data point in a highly complex environment. I am far from convinced the argument is valid at all. Sure, discourage puns in comments and [PIC] links, couldn't agree more. But I am not sure forbidding whole topics as a rule is a good idea. Plenty of smart hackers are also interested in politics, and they might not be interested in participating in multiple discussion sites. If HN limits itself too much, they might get bored and leave.

Anyway, just my speculation on an interesting topic, not trying to mount a formal argument or anything.