re: Why are angry liberal posters perceived differently than conservatives?

On this board, the exact opposite is true. Conservatives are all patriots, all liberals are socialists.

In terms of the general public narrative though, what you said is largely true for one simple reason: The liberals are better at playing the game. While conservatives spent all their time holding onto idealistic views (some reasonable, others not) liberals went out and told various segments of the population exactly what they wanted to hear.