Personally, I think of myself as having varying levels of tolerance rather than a separate level of intolerance towards someone. If someone's an a-hole, I'm probably not going to tolerate them; not because they are a different race or they believe in some religion or they're from somewhere far away.
It would totally be because they're an a-hole. That overrides most anything possibly good about anyone.
I'd probably still get blamed for being intolerant anyway by someone, especially if it was someone or some group that are so sure their beliefs are so awesome that they should be immune to any intolerance of their ideals by anyone. Then the next step in their fantasy would be setting up punishments for doing so.
So you tolerate people you meet until proven otherwise.
Oh wait. That sounds kinda bad. But that's how the worlds came out of my keyboard, so you just have to accept that.
I like to think that I have zero tolerance for people, until proven otherwise. Is that actually true, I have no idea.
Sure, like most of us. There's always someone who thinks that your point of view and thoughts are too narrow or wrong.