First, you're equating mockery of a weather woman to denial of the holocaust?
Second, my understanding of the concept of freedom of speech is this: if you don't like what somebody is saying, you
a ) ignore it
b ) laugh at it
c ) rebut it
The moment the government gets in the business of deciding what's offensive or hateful is the moment we enter the territory of censorship. You then have every single group in society lining up to sign up a new kind of speech as offensive or intolerable. That ain't free speech. That's Big Brother.