Just my opinion, but it isn't the religion. The religion is just used to radicalize people already susceptible to committing crimes for others. As Trump said, quite appropriately, they are losers. People who have lost in society and are on the margins. They don't have a purpose, and they find themselves willing to give themselves up to something which seems grander and larger. In fact they're being used as pawns, for ISIS, or for whoever.
If it were the religion, ask yourself why the profile of these bombers is always so similar. Social outcasts, petty criminals, etc. Why aren't crowned heads of states doing the same thing? Because they pay people to do it for them, and it isn't a religious matter.