Annoying pattern II

This next pattern is just as wide-spread as the first pattern I pointed out, but even more intellectually dishonest and damaging, in my opinion. It takes many forms, so I've got a few examples to illustrate it.

Example One

Me: X is true.
Opponent: That's what person A says, and person A is a jerk/idiot/ideologue for the opposite party as me, so it must be false.
me: I don't agree with person A, and I agree that they have many shortcomings, but I still stand by X.
O: Person A is pure evil. If you believe in X, then you agree with person A and thus you're dead to me.

Example Two

Me: X is true.
Opponent: You just say that because you're a/an B (note: this is a variable for a slur, not a shortening of a particular swear that begins with B).
me: I'm not a B, actually. But even if I were a B, does that mean that X is not true?
O: All Bs believe in Y as well, which is wrong/offensive/against my moral code.
me: Please stop changing the subject. We're not talking about Y, I'm not a B, and you're ignoring the fact that X is still true.
O: Whatever, B. That's what they teach you in your B literature. You've drunk the B kool-aid, you B-kool-aid drinker.

Example Three

Me: X is true
Opponent: Person C disagrees with you, and I trust person C implicitly.
me: I can show you both why person C believes what he/she does, but also why he/she is wrong.
O: Person C is never wrong/is a good person/is way smarted than you.
me: What about in this case D, in which person C has been proven to be wrong/admitted to being wrong? Is it not then possible that person C is also wrong in this situation? Can we at least talk about the warrants for X?
O: You're just a C-hater. You cannot be trusted, since you think that person C could be wrong.


These examples are often mixed and matched. Is there any defense against them? I'd like to know your thoughts on how to combat these tendencies, if they're actually justified, or if you've ever seen me use any of these tactics.