Datamined info =/= leak it's as simple as that. A leak requires a source from INSIDE blizzard, while a piece of datamined info comes from the data found in the game files that are searched through with a fine toothed comb.
IF they really did find something related to a murlocskin that would be an impressive piece of datamined info, but remember blizzard has used namefiles and other things to throw people off before.