Every religion has them
The strident vocal public attitude from the US (and observed to some extent in the Australian press) seems to be that Islam is a religion that fosters hatred and is rife with extremist groups. This is often contrasted with Christianity as a peaceful religion founded on forgiveness and tolerance.
Read what the festering extremes of Catholicism have to say and you'll get a more balanced perspective. I expect every religion has them. It's exactly what one should expect when people are taught that their identities and their life purpose are bound in their religion. Some believers can grow up and remain tolerant. Some become locked into defensiveness and anger. *sigh*
It's hard not to sound arrogant and condescending when you're discussing people who'll send hate mail and death threats over the fate of a cheap cracker.