What happens when you want to work with is indirectly based on a protected class (for example, it isn't that you want to work with a man, but you want to work with someone who fits a list of qualifications that excludes most women but very few men)?

Should depend on why you want to work with them.

You want to work with them because they are competent and results-oriented? Good.

You want to work with them because they are eager and capable? Good.

You want to work with them because they look kind of like you and like the same beers you do? Nope.

Let's just unravel what it means to not want to work with someone: you are chipping away at them as a person who is trying to survive. You are an agent of natural selection in action. If that's part of your identity, I think you're a jerk. If it's not, then hire them and offer to help them out. Don't try to change them too much - just bring them back within the normal range. Offer them CBT or just be nice to them. At the very very least, if you're not hiring someone because you don't think you can work with them, tell them, and suggest they get some counseling.