I think you're misunderstanding.

There is no reason a programmer cannot understand copyright, and there is nothing wrong with writing unoriginal software. But if somebody's going to make extraordinary, unsupported claims about the law, they need to have some experience or authority to back it up. To my knowledge, Mullenweg has neither.

If Eben Moglen said tomorrow that the GPL applies to any software in the same address space, then it would be dramatic and worrisome because he is a copyright lawyer and is one of the world's leading experts on the GPL. If the cashier at McDonalds said the same thing, I don't think it would deserve the same amount of consideration or concern.