No gambling is not restricted to some individuals or classes of people, anyone is allowed to gamble. Of course there are some age related restrictions but other than that I don't think there's any kind of restriction. If a country's law doesn't allow gambling and the country takes strict action against casinos then in such places it might be not possible to gamble, but many people even from such countries use VPNs to gamble on online casino sites. No stratification at all when it comes to gambling, like I said above everyone is allowed to gamble.
The restrictions on gambling has always been on age and not class or even financial capabilities, there are restrictions based on countries too which I don't fail to recognize too. Theses restirctions are usually placed for reasons sometimes to protect the individuals but then these people most times don't get to understand and want to just gamble especially so they can make money and not even to have fun. Every other person who's allowed to gamble can gamble but still with the caution of gambling responsibly.
Gambling should be done with care even if you are gambling responsibly then you wouldn't be bothered about been irresponsible or loosing money .