>"I mean, come on, what's more open and free than "do what the f- you want"?
>Does that mean I'm free to copyright it?
It's a license to use something to which someone else has copyright. Copyright is the possession of the *author*.
Copyright can be assigned but the *license* doesn't assign the copyright (and it can't, logically; then it would be a copyright assignment, not a license.)
You can copyright any derivative, but if you ask a lawyer the lawyer will still want to speak to the author of the original work.
That's why when you go to work for someone else they ask you to sign away all your copyright rights. Oh, no, they don't actually *ask*, it just happens when they pay you (see the 'for hire stuff', and this is only in the US, which didn't adopt standard copyright laws until very late):
John Bowler <firstname.lastname@example.org>