There are valid reasons why keeping the workplace apolitical is valuable. When it isn't, one political group usually established dominance and suppresses the opposition. The workplace becomes an environment where a subset of political views monopolize conversation, and a large portion of workers are alienated as a result. If your goal is to hire the best employees regardless of political leanings, then maintaining an apolitical workplace is a good choice.
My point is that your goals do not trump everyone else's goals just because they're reasonable business goals. There are things in life that are more important than hiring the best employees.