Re your first statement: certainly I've addressed that issue many times, but I can do it again: I don't believe that claim is true. It merely feels true to people with strong political passions, because everyone always over-weights the contributions of their enemies and under-weights the contributions of their own side. The significant thing—I was going to say "the ironic thing", but it isn't ironic—is that this class of politically passionate users all have the same perception even though they may have entirely opposing beliefs. In this they resemble each other more than they do anyone else.
I don't understand your second statement.