I can see how "poking the bear" might be exhilarating, but the consequences can spill beyond the person doing the poking.
How different this conversation would be if they shot up a daycare in retaliation.
As had already been said, it is certainly your right to offend, but be ready to reap the repercussions.
You can protest something you strongly believe in while being tactful.
Transmitted via Tactical Telecommunications Device
In your world the terrorists win every time because the person/group committed to the most violence always trumps free "whatever" due to safety concerns. One step at a time until there are no more inconvenient and offensive freedoms remaining.