I don't think this is all that specific to Reddit, though. I mean, even /pol/ was 'infiltrated' by the likes of CTR (although this of course doesn't work, since 4chan is aggressively anti-everything).
Furthermore, the fact that all moderated political (and even many nonpolitical) forums are pushed and pulled towards the extreme fringes is understandable, even to be expected: those who take moderator jobs are those who are most driven about the subject at hand, and those are most often the ones with a fringe opinion.
Furthermore, the fact that all moderated political (and even many nonpolitical) forums are pushed and pulled towards the extreme fringes is understandable, even to be expected: those who take moderator jobs are those who are most driven about the subject at hand, and those are most often the ones with a fringe opinion.