What's the hell is with all the religion bullshit

Seriously what's with a the arrogant bastards out there going religion is wrong or religion is right, hell I'm new to reddit and all this bullshit is pissing me off I'm not sure about other places but here in Australia we all get along I have mates that are Christian, Catholic, Muslim and Jewish and of course other atheist but it's never a giant shit fight so can someone please explain why there is a this bullshit flying around.