That is the tricky part because online gambling on some countries should be licensed first before they can even operate in that country. Now this Bitcoin gambling site do not cater to one country only as most of them accepts players internationally. I don't know whether what they are doing is legal or not but it maybe has something to do with them operating on cryptocurrencies and not involving Fiat Currencies, it maybe is there legal loophole that is why they can operate without even the government shutting them down. They are like Faucet sites or any Bitcoin related site.
In my country the government also banned bitcoin and its trading because it is decentralized and the government has nothing to do with bitcoin. If the people lost their money or being looted they cannot report it in government. Anyhow there should be rules for gambling in bitcoin in these countries where it is allowed and people freely deal in bitcoin.