Is it just me or are any other Americans being blocked out of the site? For me it says the websites not available in my jurisdiction. I thought most bitcoin betting sites didn't have these kind of regulations, or at least I can't remember ever having trouble with this.
Likely the site blocked people from the US. This usually is the policy of most online gambling sites, since the US has strict online gambling laws and they have really good implementation of the law which could potentially shut down the operation of these online gambling sites. That's why probably they blocked US players. Just use a VPN though, it wouldn't cause you any problems, I think.