I invent a tool and somebody else uses that tool to create something. If I create something with the intent to mimic the other thing, I am still ripping off the other person, even though I am using my own tool, because I am using it to execute an idea that is not my own.
Most tools don't come with a licensing agreement that literally says "anything you make with this tool doesn't belong to you." The WC3 editor was never their tool. Anything you make with it belongs to Blizzard. No way around it. The maps, the gameplay, the heroes, they all belong to Blizzard. The only thing that doesn't is the name, because you can easily make a legal argument that you didn't create the name using the editor.
Did they get permission from original creators?
They don't need permission because it already belonged to them. How many times and to how many people must I explain this to?