Why did they feel like they needed to repent? Alma 4:3

Why did they feel like they needed to repent? Alma 4:3

Finally the Nephites have prevailed over the Amlicite-Lamanite army. But lots of people had died, and there was a ton of destruction across the land. The death and destruction of the flocks and fields was so pervasive that, "Every soul has cause to mourn." The people believed that their afflictions were their own fault.

Answer:
It is human to seek to blame someone when something bad happens. War is not neat and tidy. There's all kinds of messy ambiguities. It's not glorious, it's a tragedy. The people probably felt like they needed to repent because, well, they needed to repent.

It's probable that some of them blamed themselves for more than their fair share of the fault, though. I think that's my own personal tendency, at least. Also very human.