The point is, JW's claim their teachings turn lion-like people into peaceable ones who can co-exist with lambs. They say their teachings are superior in molding people to be Christ-like.
But in reality their teachings of absolutism and separation from the world blind people and cause them to erect unnecessary barriers between them and their family, even their close family. That's part of what happened here.
Yes this man's actions were extreme, but the JW's were supposed to teach him to be better than that.