Nobody has 'carte banche' to express their views. I can't stand on my porch and scream at the top of my lungs "Obama is a blue lipped Marxist" and not have the authorities come and investigate if my neighbor calls them
The first amendment forbids the federal government, not the local beat cop, from restricting your speech though the power of their authority
Creating a public nuisance is not expressing your views
The first ammendment also forbids the state government from doing the same via the 14th ammendment according to the courts, so that point of yours is meaningless.
Face it Gates was a fool to behave in his boorish manner. The cop was a fool to be a “Cartman” cop and arrest Gates.