Let me site an example Straycat that I think answers your question.

We have nazis in this country. Skinheads too. I hate what they are. I despise the venom they spew. It sickens me that after thousands of Americans had to give their lives in WW2 to stop nazi Germany that there could be Americans that would want to associate tnemselves with such an organization. I see nothing virtuous about them or the things they espouse. Do you? Yet as long as they harm no one I will defend their right to be what they are and say what they say. As American citizens that liberty is their birth right and is not dependent apon whether I like them or not. It is a slippery slope to start restricting things purely because you don't like it. You are setting a precedent that can come back to bite you.

If we are only going to allow people liberty that is deemed virtuous then the first obvious question becomes, "who gets to decide was is or isn't virtuous ?" And if your answer is the majority then you have basically rendered our constitution worthless by Inventing a means by which liberty is at the mercy of mob rule.