I like this one.#7. Only attribute behaviors/events/ideas to people you can either link/quote directly, or are otherwise reasonably present in the conversation.
It's pretty common to attribute a specific event to an entire demographic, such as a terrorist attack to a religion or ideology, or a legislative effort in one state to an entire political party. This is little more than an effort to insult everyone who identifies with that religion/ideology/political-party, and is a good way to get people to treat you personally with hostility or contempt - independent of whether you're making a valid point or not.
I'll admit I can be guilty of violating this rule, especially when it comes to the American Left. I'm strongly opposed to their policies, so it can be tempting to paint every single Leftist as a villain. Realistically, though, a lot of Leftists are probably decent people who want the best for America and just have (in my view) mistaken views about the means to achieve that. My mother comes to mind here.
That said, I have definitely seen Leftists paint all conservatives, libertarians, Objectivists, etc., as villains (in various places online). So I don't think I am very unique in having occasionally violated your Rule #7 above.