This has always been a known fact but I never stopped to look at this side of it.

I know many of you will answer "war is war", but I believe there is a limit to ruthlessness.

To continue with the slaughter past the point where the enemy is defeated.

This ancient falmer tome translation illustrates the time when they had to go into hiding in fear that what was left of them would be killed off.

http://elderscrolls.wikia.com/wiki/Diary_of_Faire_Agarwen

The Nords claim to value honor, and yet they didn't cease to persecute their beaten foes even after the battle was won.

There's a lot of stuff we don't know about regarding that war. We don't know whether Ysgramor was one person or multiple, we think dragons accompanied the Nords, we don't know why the Falmer attacked Saarthal, we don't know what the Eye of Magnus is.

I reckon it was a fight over the land.