Those actions have nothing to do with true religious belief, obviously, but a religion is being used to excuse these acts of terrorism and war.

The problem isn't with the religion, which many follow peacefully, but with the violent actors trying to justify their sociopathy and cruelty based on something other than the viciousness and inadequacy of their own natures.

It isn't a lot different from Trump claiming he's acting to protect America, while reducing gun controls (where gun crimes have killed tens of thousands of Americans each year versus the very small number who perished at the hands of terrorists), and turning a blind eye to the fate of desperate refugees.  He isn't directly mutilating people, perhaps, but he's completely heedless about whether his actions result in barbaric deaths and murders, whether at home or abroad.  This is sociopathy, engaged in to advance some sense of American exceptionalism and "liberty", the religion of Trump and his followers and manipulators.