Incorrect. This man has the right to speak, but nobody is entitled to listen to him, and he's not entitled to disrupt an event. He was probably properly warned, and continued, which then ends up being disturbing the peace. Regardless, if you don't see the difference between federal authorities so-called "looking into" somebody, for what is essentially at best a misdemeanor, than you don't understand the implications behind that.
You know cops aren't obligated to warn anyone before they arrest them, right?