In general, even your country allows gambling, it doesn't mean you can access all gambling websites around the world. It wasn't shocking at all. It will depend on the game license and jurisdiction. For example, Pragmatic Plays (this is not a gaming license provider, just giving an example), wasn't available to some Asian countries like here in our country. The good thing and obviously, there are lots of game providers on certain websites.
Back to topic, this is also the first time I see a site that banned almost the majority of the regions. Let's give time OP to respond. As far as the reviews made by @BestBitcoinCasino are concerned, the site is now in the process of getting the Curacao license. Maybe that will give a gateway for more countries to be accepted by the site. It should be an obvious concern for site developers that they need to work on that.