It is no mystery that Islam is a violence prone religion.
What will he prove next, that water is wet? Maybe he will stick his head in a tub of it and stay there for a hour thereby proving that it cannot be breathed, too.
If it’s “no mystery” that Islam is a violent religion, then why do so many diplomats, Presidents, and Democratic senators have trouble with the concept?
It should be demostrated over and over and over agains, until the US of A get serious about the problem.