Religion is one of the major groups that oppose gambling as far as I know. We can't blame them because it is their religion but if they employed it into their whole country, Other religions will be affected since the law will be the one who will stop them from playing. Most vices have the possibility to make you addicted to them, Gambling is one of those vices. Self-control and Limitation is the best way to make yourself not addicted to it. It will only be dangerous if you can't control yourself from it.
If you were to compare drug addiction to other types of addiction (like gaming), it seems lenient enough, but drugs induce addiction to you, gambling on the other hand is you inducing yourself to addiction, plainly speaking, it's one's own fault, without any external influence, if he gets addicted to gambling. That's what makes gambling different from those types since gambling addiction is solely your own fault imo.
Excluding religious aspects when it comes to banning is that there are certain governments does really mind about their citizens and doesnt really mind about revenue or taxation
made out by these companies or simply on the entire industry where we do know that gambling can generate huge income and of course when it comes to tax they would really
be a big contributor but these type of government is really a bit rare or small in numbers and majority of them would really mind off about progress of their country via
tax rather than on minding with their citizens addiction probability.
I'm of the mind that regulating something instead of completely banning it is much more effective in controlling everyone who wants to actually do, well, whatever that regulated thing is, in this case, gambling. Banning gambling just gives rise to below-the-scenes development of, well surprise surprise, gambling dens themselves. It's just plain stupid imo.