AVX is a set of instructions CPUs can use. AVX is not supported on some older CPUs and if it's not, you couldn't play at all.
AVX is not needed for the Live version of the game, and it also won't be for the beta. The graphic just shows having AVX or not enabled
in the game code didn't have an impact on performance, so they could just remove it and have the maximum amount of people able to play.