Lol. Most harm to anyone, regardless of age, is caused by friends and family, but that is primarily because friends and family have the most opporunities.
If strangers were afforded equal access to your children, the numbers would not be so favorable. Having strangers around does not make your kids safer. At best, your kinds would be just as safe around strangers. At worst, they would be exposed to far more risk.
Where is the data to support your claim? It's possible that strangers are more dangerous on a per opportunity basis, but I suspect it's untrue. For example, children spend about the same time at school as at home (at least on weekdays). Yet abuse is much more frequent at home.
If strangers were afforded equal access to your children, the numbers would not be so favorable. Having strangers around does not make your kids safer. At best, your kinds would be just as safe around strangers. At worst, they would be exposed to far more risk.