With e2e encryption, the signals you have are pretty minimal.

Let's say a 40 y/o man finds a phone on the ground, sees a name stuck on it, googles "name + town" and finds the facebook of a 12 y/o girl, and messages "Hey I found this phone, do you recognize it? <photo>"

With e2e encryption, you can't easily tell the difference between that and a creep.

This thread is advocating that exactly that case should result in a police visit with the assumption of guilt.