My response to that: You do not know.
Nobody wants to imagine that they personally know someone who is an abuser of anything, let alone a child abuser. But the reality is there's no way to know. With the exception of the most extreme, abusive parents don't stick out like a sore thumb, especially not when the abuse is non-physical.
I have said before if, somehow, I had a child and did give it up for whatever reason, I would not be an abusive parent. But I don't know this. This would be my child, not someone else's child I can send home when they get irritating. I have to tend to this child's needs. I wrote a previous post about the toll the stress would take on me. What if the stress and exhaustion became so much, I abused my child? It's easy to say I won't, but I have never been under any severe stress I couldn't handle. In a situation, in circumstances I couldn't do much of anything about, what would I do?
Of course, this doesn't apply to all childfree people. Not by a long shot and I can safely say I would never abuse someone else's kids. But my own would be a different story. Nobody who knows me could guess I'd be capable of such a thing. There's only one way to find out if I am and I'm not doing it.