When I discuss the wide range of gambling and betting with friends who are not on the forum, I often notice their flawed thinking. If it were just once, I would not have given it a thought but when their flawed thinking about gambling comes up over and over again it makes me torn between wanting to help them change the way they think or just leaving them to continue with such thinking until some major gambling experience happens and changes it for them. Some type of this flawed thinking is borrowing money from loan apps to gamble thinking that when they win they will pay back the loan and its interest and keep the rest for themselves. They call this gambling, with other people's money. Another flawed thinking is their belief that paid between groups will make them become millionaires faster than if they are not in the paid group. There are others like this.
If you are that kind of person that is argumentative and confrontational, then maybe you can correct them. But personally, I'm not that kind of person, although I have once a argument against someone regarding gambling but I didn't take it personally. We might have different views on it so at the end of the day there is no winner and we still are friends. But if you don't know the person that is in front of you that much, it's really have to argue with them and so just let it be.
For close friends, why not? Maybe they will take your advise and find it true to save them some money. Or maybe they will just laugh it off and after the argument, there is no love lost between you and your close friends.