Certain protections for minors applied only to People You May Know and did not extend to other parts of Facebook

"One method we're using is to remove minors in inbox search for unconnected adults… You can typically search for people you are not connected w/ in Inbox search (i.e. start a new message w/ someone you're not connected to in this way); this blocks that feature… If minors are discovered through other mechanisms, FB and Messenger have special protections in place for minors… At the moment, we only have risky adult <> minor filtering on People You May Know for FB Blue - so the above does not apply to blue"