This is not a problem of extremism its also a problem for the nice little old lady who goes to her nice little conservative church on a Sundy and prays that her nice neighbour might get saved.
That particular instance is pretty benign. Now if the granny tells her grandchildren that their daddy is going to burn in hell for leaving their mommy that poses some unique problems. You need to attack the delusions that are harming people, not the right to have delusions. Pick a fight you have a chance at winning. If you treat religion like it's a hive collective and search to destroy it's heart you will die trying. It will just be a bunch of broken hearts because it's too much to ask from some people to not believe or to feel second class because they don't have empirical evidence of their deity.
In the first century the Roman empire crucified thousands of people for rebellion around 70 AD. Why do you think they felt justified in treating these people this way? Rome was a learned state and they skyrocketed in awareness of their environment. Only because they provided a perfect way of life for a select population caused by hoarding war technology. To the Roman citizen there appeared to be two classes, learned and unlearned. Unlearned people did not get to stand up for what they believed in because they were operating on false assumptions. Examples were made out of them.
Religion is poison.
The Roman's were poison.
-Sab