Or, "I may disagree with what you say, but I'll fight to the death for your right to say it."
That sort of thing.
Except, as usual, Neil Gaiman says it much better.
The Law is a huge blunt weapon that does not and will not make distinctions between what you find acceptable and what you don't.
Popular speech doesn't need defending. The speech (fiction, art, whatever) that makes you cringe and snarl and want to hit something is what needs defending, and we all need to defend it or next time it'll be our speech or fiction or art which makes someone else cringe or snarl or want to hit something, and we'll be left blustering about how our writing is different.
No. It's not. To that other person out there, my writing and your writing is just as objectionable as that other stuff you or I consider disgusting or obscene. It's all the same to someone, and that someone might well be trying to get re-elected. So we need to defend it all, simple as that.