Some of it has to do with motherly instinct.
Christians are humans too. And sometimes Christians are bad news, or their kids.
I have a neighbor who is very Bible oriented Christian. She has one disabled daughter and an older girl. The older one is sneaky and violent. The mom spends tons of time and energy taking care of the little one so the older one has problems that she doesn't see or doesn't want to.
Although we used to be close, a few incidents caused us to pause. I thank the Dear Lord that nothing has happened so far. I have heard from other mothers in a homeschooling group that I don't belong to, this girl is getting worse.
I think that for the most part when something is done by someone who claims to be a Christian that the person had a false conversion, of the mind but not the spirit. Backsliding is always possible but if there has never been fruit evident in their life it's cause for question.
My son was attacked by some other boys the other day at a church event. Thank God it was over quickly and he wasn't injured badly. Unfortunately those boys were allowed to stay for the remainder of the event with a stern warning. I was called at the time of the incident due to my son's injury but the other parents were not called and that was wrong. So we have to deal with the situation with our church leaders this week. I learned last night that some girls had jumped a girl at church some weeks previous. We are living in perilous times!