Muslim or Christian gambling is both sin for all of us. Let's remove religion with this, gambling is a business entity that is for everyone and is free to do it unless the state is prohibiting doing such act that relates to gambling. Because there are countries that ban gambling and completely disallows people for doing it so and I think it's mostly in your region.
In Islam gambling is a mortal sin and you will be against the law of Quran so they are not allowed to gamble. I have a lot of Muslim friends and they are really following their low and they don't want to commit a sin like gambling because they treat the law holy but in my thinking, there's nothing to treat a sin as long as you are not destroying others reputation and using others money.
Once sin remains sin, in Islam gambling is sin. So whatever your reason for gambling, however you treat it, gambling remains a sin in Islam. And if you know that gambling is a sin, but you do not care about it and keep on gambling, then you're against the rules and that's the worst thing.