Why do they (terrorists) hate us (americans)?

I Just watched “The Kingdom” and the ending was very powerful. Spoilers ahead if anyone hasn’t seen it yet…So a (radical) muslim male feels like he has a religious right to kill as many westerners as possible and western forces job is to hunt and counter these poeple. True? Back to my OP why do these people hate us so much? Is it purely difference of religoin, or capitalism? These people are willing to die for a chance to kill or even wound any of us (americans). Response?