I said "insult and berate," not "threaten." Of course, exercise of free speech rights does not exempt anyone from other applicable laws. But then, engaging in photography doesn't exempt anyone from other applicable laws email@example.com said:Orangutang, I must respectfully disagree with you. It is correct that I have the right to shoot whatever is publicly available. And onlookers (including police or security guards) do have the right civilly and politely to ask me about my activities. But they do not have the right to threaten, harass, detain, intimidate, or in general cause fear or disruption to me. If I as a reasonable person (and I do NOT mean those professionally-offended professional victims) am intimidated or made fearful by an insulting or berating onlooker, I have the right to be free of that intimidation. (The handout on the adkins website is quite clear on this point.)
The US Supreme Court gives wide latitude to free speech: http://en.wikipedia.org/wiki/Snyder_v._Phelps
In short, someone is legally entitled to come up to you and call you all manner of nasty names for any reason, or for no reason. So long as it doesn't cross that magic, legal line, it's "free speech."
If you want to stand on the law as written and decided by the courts, it applies both ways. If you want to celebrate your own right to engage in activities that some people would find offensive and intrusive, you should be prepared to celebrate the rights of others to engage in activities that you find offensive. My argument, however, is an ethical argument, not legal.