Outlawing a religion is like trying to stop booze or prostitution won't happen here.
There is nothing like creating martyrs to swell the ranks of a religion. In the early days of christianity it was the Romans feeding christians to the lions that cause it to become such a dominant religion. It was like, "Hey people are dying for this belief so it must have validity" then they would jump up and down in front of soldiers and shout, "Pick me!"
Now, for some bizarre reason, some fanatical Muslims thin that, "Hey, that guy just blew himself up in a crouded market for Allah. This religion must have some validity. Pick me!"
I hope that sounded really silly because it makes no sense to me but somehow it makes sense to Christians and Muslims.