Comment by jandrese

It makes sense. Convincing someone to go kill other people so they can take their stuff and rape their women isn't that hard. The personal benefit is front and center, it aligns easily with human nature.

Convincing someone to go kill other people so you can get their stuff is a lot harder. You have to get creative with the reasons, and even then you had better be giving those fighters their cut unless you've really managed to get them fully committed to whatever excuse to made up. It helps a lot if there is some kind of wedge issue you can exploit, which is where religion and ethnicity come in handy.