Comment by octaane

To avoid mass casualties at the end of the runway - on the road, or the buildings that the runway points to. Check the layout on google maps.

More specifically, V1 is the max speed at which you're about to take off, but you can still abort from. They hit that max speed and realized there was a major problem that hypothetically, they could have slowed down from, but realistically was not possible. They had no choice.