You keep records of prospects. In his, you note what you said. You are not responsible to rent to people with personality problems. It does not matter whether it is a minority or anything else.
The law talks about protected classes. As someone said above, this is not a protected class.
If someone threatened you, would you rent to them? Of course not. Same for personality problems. You are allowed to screen against people who make you uncomfortable (as long as not for reasons of protected class).