In Hustler Magazine v. Falwell, why, specifically, did the Supreme Court believe it was necessary to grant constitutional protection to the outrageous ad parody?

What will be an ideal response?

[Because the sort of robust political debate encouraged by the First Amendment will inevitably include caustic and sometimes unpleasantly sharp attacks on public officials. If liability were allowed in this case, then political cartoonists and satirists would be subjected to lawsuits without any showing that their work falsely defamed anyone.]