We’ve been all but pulling the trigger as we supported Saudis bombing them for years, kept them under famine, have American mercenaries doing political assassinations for the emirates in Yemen, the list goes on.
We had 9/11 happen and large chunks of society wanted to nuke Mecca. Imagine multiple 9/11s every year for a decade and think how you’d feel.
If these people won, and all of the people they hate so much died tomorrow, would they stop killing? I think not. I suspect that they would begin killing other sects of their own religion, and after that people who don't adhere closely enough to the rules of the "one true religion".
Murderers want to murder. In the end, the reasons are made up long after the decision to murder is made.
Can they be rehabilitated in some way?
You should think deep why you assume they are simply killers and not people with dignity who have been wronged by the murderous governments of saud and the us. And you should be asking if we are the ones that can be rehabilitated.