That is the prime essence of evil.
It seems to me that some people just deserve a double portion of millstone around their necks.
That I think is definitely covered by Christ’s “millstone admonition”. It is totally evil in that they were telling the boy that there was no God that could save him and that there was no true justice....only that which could be reinforced by force and by hate. Your account fills me with horror and rage as to what happened to that little boy!