It's not really hypocritical but may seem contradictory. Primedice are likely just trying to comply with US gambling laws but you can always get around restrictions by using a proxy or tor which I suggest you do if you want to play.
Not contradictory , they know users can get around the restriction by using TOR, but then its not their fault, but the people's who use such ways to access the site. They are just safeguarding their site for the future.
How far can Tor get you through this?
What happens when you get caught? Will the US gambling laws get you end up in jail?
Nope, never going to get you in jail. Even the people who gamble through other ways, at max have their accounts blocked, or just a warning. Its not a very serious crime, afaik.