I will literally never choose to watch a disturbing but real event. War crimes, either in the form of documenting them or promoting them, will be flagged as "people like Ben never click on previews of this video, don't waste time suggesting it to them in future". I won't even get as far as the page the flag button is on, never mind any other options.

Sounds like the system would be doing its job in that case.

Only insofar as the system is there to make me spend more time watching videos; it does nothing to help categorise or identify propoganda that isn't targeted at me.