Becoming religious does not make you violent, but going to Afghanistan and becoming religious can. When in Afghanistan and seeing grown men have sex with young boys and goats after maghrib it's pretty difficult not to judge.  When their 'prophet' and founder Mohammed married a 6 year old and was screwing her by 10 years of age, respect is hard to come by, I don't like pedophiles.
Verses in the Qur'an call for violence against all who do not believe in Allah. 
I know good people exist who practice Islam but the radical Muslims are like an ever spreading stage 4 cancer.