Most of the moderators and posters are liberals, and are afraid of being accused of being unfair to conservatives, a situation which the conservatives have very deftly exploited. The result is intimidation leading to self-censorship, and a shifting of the definition of "center" way to the right. The right, in turn, interprets this as evidence of the weakness and cowardice of the left, which validates the contempt they feel for it, and justifies further attacks.

The anomalists have less sympathy from either side of the political spectrum, so it's ok to gang up on them. It's something left and right can agree on.

Again, it must be emphasized that the term "political post" is only shorthand for a post which attempts to monopolize the conversation and shift the focus on to partisan issues, not just a comment on a particular issue. The perfectly legitimate tactic of criticizing a policy soon gives way to criticizing a policy solely because it is being proposed by the other side. From there, it evolves to criticizing all the policies of the other side, until eventually, the other side is being attacked for its very existence and it's potential responses to situations that haven't even happened yet. The "other side" soon finds itself not only defending itself from attack continuously, but defending its very right to exist. This is a long way from just having two voices on opposite sides arguing a difference of opinion on policy.

Deliberately setting up this caustic environment is a favorite tactic of propagandists who know they cannot survive in an atmosphere of tolerance and civiliy. It is also the final tactic of partisans who are on the defensive, who see their philosophies and policies being rejected in the courts of public opinion and history, and who sense that their party has been discredited by the exposure of its corruption and incompetence.