I don't know how far your casino platform is, but it should never be limited to these few countries. You need to expand to more countries and allow gambling (in countries where casinos are legal), then the casino platform will attract more gamblers. Because I think gamblers exist in all countries of the world (secretly or openly), but I think the more countries you allow, the more popular the casino platform will be for gambling and betting.
Did not understand how they restriction only these few countries. Although we don't know about the restricted on their platform, there is room for improvement in their restricted, such as if they restricted all the countries where casinos are illegal, they must restric.. them. Moreover, if only a few countries restricted them, the situation becomes different.
However, personally, I think it is better not to restricted them, so that casino players can freely play the game from anywhere. This will be good for the casino site, as players from everywhere can play the game very easily and it can be a good medium for them to become popular. I also agree with the points you have raised. If the ban is imposed like this, then it is right.