The dislike of Tau isn't terribly prevalent anymore these days, and much of it is mostly in jest. Everyone hates every army they don't play in 40k, except maybe the Orks. Besides, they aren't very overpowered these days. 8th edition is the horde edition, and is favouring forces like the Imperial Guard, Orks, and Tyranids more then last edition, which favoured Death Stars and powerful shooting armies, like the Tau. Much of the current dislike for Tau mostly stems from the massive range and shooting power the larger battlesuits have. Some can more or less shoot anything from anywhere on the board. Since this isn't nearly as much of an advantage as it was last edition, the remaining salt will probably die down eventually.