No, there isn't unlimited free speech, but the rally and the subject of this article are within those limits according to the courts.
That is not to say the group doesn't have to follow local ordinances that are within reason, just like Westboro does, which may lower their visibility. But as long as they meet the conditions, what they are doing here is legal.
I was always addressing your "bait them" comment. If that's the intent of this rally, that along with the signs and the shirts will void out their First Amendment rights.
From every bit of film that I've seen of the event, the rally was held across the street from the mosque, with protesters and counter protesters at times standing nose to nose to one another. The local police formed a line dividing the two, and they were merely shouting at one another over that line, with a number of Muslims holding signs that read "F#CK ISIS NOT ISLAM".
The point is that you cannot intentionally set out to do something with the intention of inciting someone to engage in violence. The may very well engage in that violence and ultimately win the legal argument over who started the fight, and who was guilty of an infraction.
Other than that, those two that were shot dead in Texas deserved what they got.
I just don't see the point of the "Draw Mohamed" contests. We already know that we can do that with no fear of government interference.