Good Muslims are supposed to give non-Muslims a warning, to demand that they convert to Islam or else, before they actually do the “or else”.
In this situation, I think turnabout is fair play. A bunch of the people in that mosque should be sent an easy to understand guide to what constitutes “criminal incitement” in the US.
Fair warning that instigators at that mosque had better shove a sock into it, or they may invite criminal prosecution.
You didn’t hear about a guy named “Obama” being elected to the White House back in 2008?