Beating a 14 year old for not wearing a hijab is not radical to them.
That's the problem. These whackjobs don't believe they're radical.
This happened in my area. inquisitr.com/2591770/word-of-life-church-8-members-indicted-for-savage-beating-death-of-lucas-leonard-19-for-wanting-out
I'm against all fundamentalism but find it ironic when people say there are no moderate Muslims, Jews, Christians, etc...
It comes down to the simple question: Is tolerating an extreme practice/sect within your religion the same as endorsement? If it's "Yes", You're agreeing with them on some fundamental level. If it's "No" then some responsibility exists.
Accommodations I consider extreme are made all the time (in Brooklyn, for example) but anyone who doesn't play along would be called culturally insensitive or worse.