The original link also has an edit after it reading:

Edit: So this is the edit where I get to feel like an ass. As many of you know, I never usually post information about a demo until it is actually available on the Xbox LIVE Marketplace. Well, with this post I went against that little voice in my head and gave you a heads up. I just received an email that proves I should have listened to that voice. It turns out the demo will NOT be available in Canada and the U.S. (in addition to India and Germany as noted above.) I don’t know when a demo will be available for the other regions, but hopefully it will be by the end of the week (as originally stated.) My apologies. You can be sure that I am going to have a a few conversations with a some people about this.