Google this: "Snitches get stitches"**
If I may ask: how many posts have you reported? You seem to think reporting posts is a bad thing, I think it's a good thing. It's like calling waste collection when there's a pile of trash in your area.
You don't need to certify him on the ground of reporting as many post as possible. Reporting post isn't bad either, it ensures the safety of everyone from scammers, spam messages and also post that isn't suppose to be under certain thread. No need to justify your point. But we need to have substantial evidence to back-up any report in order to avoid tarnishing identity of any member then up end retrieving such report.