A Muslim preacher crashing a concert, or whatever that was going to be, was rude as hell. Worse than the Seventh Day Adventists who knock on your door every Sunday. Of course they should have gotten him off the stage.
I'm not sure what other point you were making. Was that it?
Those in the audience who clapped for him should run out and get to a mosque. If they're women, they are advised to purchase a hijab or burka on the way, as they would no longer be "free."