Board Thread:Episode Discussion/@comment-34633327-20171118002715/@comment-2001:56A:70D3:E700:E534:78EF:588E:8DB4-20171126094740

Kind of late to the party, since I watch via Crunchyroll, but on the subject of of Salem and the Grimm eventually killing themselves through the desctruction of humanity, I beleive it is simply their innate programming to do so. They were created to destroy everything created by the elder of the Diety Brothers, if you take the Remnant Creation Myth as face value.

So they're simply doing it because it is their prime directive.