That is a ridiculous statement. For how long have you played the game? World of Warcraft has not always been so well designed, and in the beginning of the game there was a vast difference in how well different classes earned gold, some classes didn't even have a viable DPS spec. In addition to get fast wow gold that, Blizzard asked for a stupid number of consumables to raid, a large quantity of gold just to ride at maximum speed (100% riding speed was crucial in vanilla BGs) plus insane repair bills on raid progression (40 people dying per wipe = one heck of a gold drain).
Then came TBC where the first tier riding skill was slower than a ground mount (60% flying speed) and you needed to purchase the expensive riding skill to unlock content such as Netherwing daily quests, and without fast speed you couldn't even farm anywhere near the same rate as your clustering competition.
With other words, Blizzard *created* the need to buy gold. There's a reason they suddenly realized riding skill prices needed to go down, the number of consumables went down, repair costs were equalized and no cheap wow accounts content required an expensive gold donation. They learned from their mistakes, but they still invited gold farmers into the game by creating a need for which there was no supply.
As gold has gotten easier to earn, so has the amounts you get for your money increased. Blizzard already sells special mounts in their store so what's the difference between buying a mount from Blizzard or buying gold to purchase a mount like Vial of the Sands? Because Blizzard says it's "cheating"? Hm?
I don't support buying gold because of the methods gold farmers have resorted to sell gold, like scamming accounts (my nephew's account was hacked). But gold farmers didn't always use such methods, and Blizzard gave gold farmers good reasons to sell gold in the game.