Gaiman posts a lengthy and well-reasoned examination of the need to protect even speech we may find distasteful. Recommended reading. Excerpts:
I loved coming to the US in 1992, mostly because I loved the idea that freedom of speech was paramount. I still do. With all its faults, the US has Freedom of Speech. You can't be arrested for saying things the government doesn't like. You can say what you like, write what you like, and know that the remedy to someone saying or writing or showing something that offends you is not to read it, or to speak out against it. I loved that I could read and make my own mind up about something. ...Some nations imprison people for self-expression, like the Burmese blogger recently sentenced to 20 years imprisonment for lampooning the military. We can be thankful for freedom of speech as one of our American national cornerstones, but can't take it for granted.
Freedom to write, freedom to read, freedom to own material that you believe is worth defending means you're going to have to stand up for stuff you don't believe is worth defending, even stuff you find actively distasteful, because laws are big blunt instruments that do not differentiate between what you like and what you don't, because prosecutors are humans and bear grudges and fight for re-election, because one person's obscenity is another person's art.
Because if you don't stand up for the stuff you don't like, when they come for the stuff you do like, you've already lost.
... that's what makes the kind of work you don't like, or don't read, or work that you do not feel has artistic worth or redeeming features worth defending. It's because the same laws cover the stuff you like and the stuff you find icky, wherever your icky line happens to be: the law is a big blunt instrument that makes no fine distinctions, and because you only realise how wonderful absolute freedom of speech is the day you lose it.