I am locking this topic because two wrongs don't make a right.
There is a reason for the under 13 age rule. If you are going to accuse someone of doing the wrong thing, then you must come into it with clean hands. OP, you aren't coming into it with clean hands since you have admitted that you are letting your under 13 child have a page on FB. Regardless of how much monitoring your are doing, the rules are still being broken.
We must all consider the consequences of our actions when we attempt to accuse others of bad consequences.