People love complaining about YouTube comments, and I do too. I disagree with lots of people in YouTube comments.
People also love hating democratically elected leaders; which is their right. Among the people I know, it's common to hear people saying "Stephen Harper doesn't do anything right" or "Rob Ford should never have been elected". I'm not really in a position to evaluate these claims and probably agree based on what I know.
But what I don't like, and want to fight back against, is people saying that "everyone who ever voted for [the leader I don't like] is an idiot". You see this in a lot of forms. "How could anyone ever vote for [the leader I don't like]" is another great one; it demonstrates that the person saying it isn't even willing to consider the positive sides of Rob Ford or Stephen Harper. That is what I call partisanship.
I'm a militant centrist; I don't like partisanship and don't think you should like it either. This is a trendy position. In the USA, members of Congress are starting to fight back against the influence of hyper-partisan voters by voting against the dogmatic party line once in a while. Centrists create better policies and swing voters decide elections. Partisan voters that identify with a party more than the issues create stubbornness and erode empathy for the other people living in our countries.
You can say lots of things about our leaders, but if the way you say it shuts down dialogue about the good and bad of their policies, you are a danger to the kind of democracy I want to live in.