oblique hate discussion

Character Development: Oblique Hate

I was thinking today about what it would be like to have a character who is perfectly nice to your MC—maybe even the nicest person the MC meets over the course of the story. But there’s a downside. That lovely, generous, kind character has an intense, murderous hatred of a group of people (such as racial groups, religious groups, etc.) that is the product of ignorance and/or prejudice. The MC is not a member of this hated group and so is not exposed to any of the prejudiced wrath of the “nice” character.

How would you approach something like that in your writing?