It makes some amount of sense to me. If I lived a nomadic existence and a larger more powerful tribe drove me out of some territory I'd be angry but eventually just try to find new territory since I'm mobile anyway.

If I was a farmer though and my crop was being stolen I'd probably fight to the death. I wouldn't be able to easily replace it and if I was driven off the territory my group would probably starve before we could locate a new site a establish a new farm.