Yes you are right This is just a game, but sometimes most of us treat it as a source of other income if you cannot control it you will lose, believe me. I have already been there. Haha
Maybe there is a fear of gambling addicts that if they reveal their gambling addiction to other people, they will be rejected by people, making them unable to accept it. And that's what makes gambling addicts not want to admit that they have a gambling addiction so they don't dare to be honest with other people. But if they don't care about what other people will say, they will still say or be honest with people that they need help and want to cure their gambling addiction. That will allow them to get the right treatment to cure their gambling addiction.
Also, agree with you that sometimes a gambling addict closes himself, If I had a friend like this I would talk to him because sometimes talking to other people can relieve such a burden in the back
They would literally feel rejected since we all know that gambling has a risk factor that could destroy someone's life, and they know to themselves that gambling should be done responsibly. Still due to problems in life or issues, they thought gambling as a source of income, source of fun, distraction and etc. But of course it doesn't solve anything as gamblign worsen your life situation like being in debt. Maybe asking them or being there for them could lessen their gambling addiction which is better than risking all of your funds. But for me, going to doctor is the best, like going to therapy which could literally help the person with addiction or depression.
That last resort if gambling already being out of control, when addiction already dominates and there's nothing that the person wanted to do in life all is to please his gambling participation, yes, therapy or specialist will help to bring back that control inside that persons' mindset, though it's difficult when the person still in the stage of denial, still believing that he's doing fine and there's nothing wrong with his gambling participation.
That kind of thing needs physical companionship as to push the person to lessen his gambling sessions. You need to find a way to divert his attention and to help him to move that focus to gambling.