Muslims are killing people who convert away from Islam. Are you going to ban that religion?
Religious groups like the Amish shun people, which is emotionally painful, but you can move on with your life.
And if you want to talk about "should we prosecute shunning groups?", how do you address Social Justice Warriors who seek to not only shun those who don't agree in lock step to a long laundry list of ideas but seek to cost them their jobs and social reputation online for it? The Amish and cults may shun you, but they don't try to make life impossible for you in the outside world - but liberal radicals are.