I really doubt this is ever an effective way to teach a child not to bite. And at least one of these bites was on the 2 year old's genitals. This guy needs a permanent home in a secure psych hospital.
I mean that a normal parent who bites a child’s arm when he bites another child (not hard enough to leave a mark, but hard enough to get the attention) is an effective way to stop most “biters” when they are young.
This guy repeatedly bit a child hard enough to leave marks hours after the event and bit the child all over. As I said above, he is a danger and needs to be locked away.