Why require login to unsubscribe from spam?

I think most people create a lot of accounts in this Internet world. Most of these accounts are silly because there is no data of interest, and nothing to protect. Two such accounts, like those at Auctiva and JBoss.org, both spam you when you sign up for an account, and both require a log in and manipulation of email preferences. Of course, I don't remember these accounts, and, really, I don't want to go to that amount of trouble. Which means I hit the spam button in Gmail, which is easy, quick, but makes it possible, if not likely, that neither companies newsletters will make it even to legitimate customers. Which is something I know neither company wants.

Come on people. Make it easy to unsubscribe (like, a single click). It's a Good Idea.