Relax. No they aren't.
Blizzard is releasing a new pet, a miniature of the guardian mount this time. What's unique about that pet is that it will be BoE and a one time use. Of course, that means you can buy it for real life cash and then sell it on the auction house. This created a commotion in the community, with many people shouting how it will ruin the economy, how it creates a precedent and puts us on a slippery slope. This is just plain wrong, at least when it comes to ruining the economy. This is why.
Gold buying is common in WoW, it just isn't legal. I'm willing to bet most people did it, or at least know someone that did it. Now it's legal and it's better that way. Why? Illegal gold sellers get their gold from several sources, but the biggest one are the compromised accounts. Heck, most people that buy gold do it in a dumb way which then gets their account hacked soon in the future. So what happens when your account gets hacked? You report it to blizzard and get your items restored. The problem is, the gold that will be restored to you is created out of thin air, while the hacker still gets to keep his gold. In fact, he already passed it on to buyers or someone else, which is why Blizzard can't just remove it from the game - someone else, often innocent will get damaged that way. So suddenly there's more gold in the game and everyone's gold is worth less - inflation.
On the other hand, if someone buys this mount in the store and puts it on the auction house for, let's say, 40 thousand gold, someone will buy it and suddenly there's 40 000 gold less with that player. It just changes hands, no inflation happening. This is why it's a good thing.
Of course, the reality isn't that simple. In all likelihood, illegal gold selling will still be there because it will probably be cheaper. Heck, this might even encourage more people to buy illegally, since they might get the pet cheaper that way. Still, in most scenarios I can think if, this might not shift the game in another direction, but it certainly will help slow the inflation due to hacking and farming down. This is always a good thing, especially for those who don't have time for farming or playing the AH like I do.