Equal employment laws and anti-discrimination statutes are real things, and they spell out which groups are protected classes - those based on race, sex, religion, disability, etc. Your workplace is not your living room, and not all ideas and behaviors are equally acceptable. I don't believe conservatives should be discriminated against, but when "conservative" becomes a euphemism for pro-white/anti-semitic/misogynistic beliefs, then you may find yourself running afoul of laws or corporate guidelines because those things are not on the same level as "should taxes be higher or lower" or "what's the right level of environmental regulation."