Freedom of speech, has it ever been overexercised to a point about our military?

I'm 16 years old and after high school i'm enlisting in the Marine Corps because I feel that it's an honor to serve my country. When people that have different views, such as organizations that go to extreme measures to protest, like code pink, does it really give them those rights to impersonate Marines (like one did in Berkley, California) hold up signs that say "We support the murdering of United States Soldiers", and paint red on their cheeks to mock soldiers that have died. And then they go ahead and say "it's a free country, we can say anything we want". Do you think that our Amendment to free speech is overexercised to a certain degree, where the creaters of the constituion would be dismayed?