The problem then is what whitespace do you keep and what do you ditch? The default behavior you want is to maintain everything inside. But I agree the - tag seems like a really inelegant hack.
What? They could have done any number of things. They could have added a parameter "-trim" that's more clear than the "-" alone. They could have made it "8<" that looks like a little pair of scissors. Or they could have actually spent some time thinking of a good idea instead of those ones that are about as a bad as the one they went with.
The idea they went with, which was one of the ones I proposed, is used in a variety of open source projects, so it had the advantage of being somewhat familiar and vetted. And what I meant to say is that they had to modify things in a backward compatible way, which means keep whitespace by default and trim with new syntax.
