No because it happens a whole lot more than you think. You wouldn't believe what comes into the ER. I'm not talking black eyes. In some cultures, scalding water is used as a form of punishment. The kids would come in with the skin peeling off. I knew of a church in Gboro that would go around picking up kids for church in a bus. They would feed them and give them food to take home because the parents drank everything and there was no food in the house.
This stuff exists. The problem is that families get in fights and they start slinging accusations as a form of negotiation. I know of one family now where the wife is claiming abuse to get child support. CPS has to wade through all this crap.