Sorry, but I disagree. You don’t get to be picky about who agrees with you on a certain issue. Politics is all about building a coalition of 50.1%. Work with whoever agrees with you on a specific issue and that's fine. Besides there is a small chance that you can get him to soften his views just by working together. Forcing them to go sit on the naughty step because they have one abhorrent view or another does nothing but isolate them in an echo chamber where they can fester and spread their asinine world view. Even if it is frustrating and difficult it is better to show them your humanity and try to be an example of a good sane person then to shun them just to feel morally superior.