You can find asshats in any belief system as well as good people.
I have a pet theory (poorly validated) that younger religions tend to have more severe extremism at the fringe because they're just insecure about being newer.
(look at Christianity and Judaism in their younger expansionist days) ... but some people have
used religion to justify horrible violence as far back as you want to go. Defanging and cloistering the wingnuts is tough when moderate people are.. well... moderate.