You didn't answer my question: Where did Blizzard say that "engineers" are the only ones dealing with technology?
As to your question, we know that a Warrior is a fighter and a King is a ruler. A person can be a warrior and a King. That isn't the case here though, because calling an Artificer an Engineer doesn't make sense. An artificer deals with magic and technology, usually revolving around artifacts.
It appears more logical that in a world of 13 sentient races and several different branches of technology, the people of Azeroth would simply call their technology experts many different things. To say that they're all "engineers" and that anything that is not an engineer has "no place is WoW" is a very narrow view not backed by any evidence.