Actually, it does let you play SC2 against computers via the test map feature. If you are trying to claim that you want to make maps just for the sake of coding them and not being able to play or test them in any way, shape, or form, I have a really hard time believing that.
But if you are testing them, then you are playing games in the SC2 engine. You could easily ask your friends to send you the campaign, so you could play that too.
Trying to say that Blizzard is greedy because they don't feel like specifically catering to players like you who aren't even buying their game is pretty stupid. Oh yeah, also, I don't think the world editor could be used for free either (legally).
Finally, your note on piracy.
So basically, because you think that it shouldn't cost $60 to use their editor, you think you should get it for free. After all, it's not like people actually put effort into creating the editor. Like it or not, the editor is a part of the game. People put effort into making it into what it is, because it's their job, because they are getting paid for it. It isn't their job or their responsibility or their moral obligation to provide you with free things out of the kindness of their own hearts.
In short, if you don't want to pay $60 for the map editor, don't use the map editor. Doing anything but that is arrogant and immature (and whining on a forum about how "penny-pinching cunts" simply don't want to provide you with free services really doesn't help your case).