Sorry for the confusion. They blocked US players from their website where they could get information on what was currently being bet on and where to send their Bitcoin.
IIRC Satoshi Dice worked by sending Bitcoin to a specific address for a bet and the address changed each time which they displayed on their website. By blocking US players from the website they could legally claim to be in compliance with the regulation (IANAL).
Well some months ago it was a separate landing page, but I guess they changed it. They still don't display the information unless you agree that you are in a legal jurisdiction to use the service.
IIRC Satoshi Dice worked by sending Bitcoin to a specific address for a bet and the address changed each time which they displayed on their website. By blocking US players from the website they could legally claim to be in compliance with the regulation (IANAL).