The attacker's motivation was apparently to promote worldwide racial and political balkanization by increasing the solidarity of all groups while also pushing them apart. He wanted to increase tensions between Muslim and Christian, white and non-white, left and right, etc. So he's probably very happy with the world's response so far, including some of the reaction in this thread.

The attack itself was evil, of course, and this underlying goal of promoting collectivism was both particularly evil and worryingly effective.