I thought it was just me. The good news is it's an ebb and flow. It comes and goes a few days apart. When I first noticed it I freaked out because that's how it happened at Digg and Reddit. It began with the politicization of topics then the over-politicization of topics and before you know it the moderates left and the fanatics ruled. On hacker news there's enough variety to balance it all out. For now. And hopefully for a long time. Older members should know what I'm talking about.