If anything this just shows how different the Alliance and Horde are, the gnomes refused to tell anyone their problems back in Warcraft 3 precisely because they knew the rest of their allies would try to help them at the expense of trying to help Lordearon at the time.
Back on topic, Sylvanas still proves she didnt care one bit about the elves and that ultimately anything she gives to someone has a price, sometimes a very dire price. A lesson anyone following her should know by now.