I basically think like this as well, there is a difference between teaching a kid how to gamble, a very irresponsible thing to do, and teaching them how gambling works and why it is not a good idea for them to participate in it, this way in the case one of their peers tried to introduce them to that world, they will be prepared to take a responsible choice and stay away from it, unlike what happens to those that are kept ignorant about the dangers of gambling at such an early age and decide to try it because the rest of their friends are willing to do it.
Another one that has illusion that if a kid see or know what is gambling, he will turn into addicted gambler. Can you try to describe what harm gambling can do to a kid without using words addiction, money or irresponsible?
I see two different approaches about teaching kids what is gambling. First is when you explain, teach rules, gamble with a kid. Second is when you teach that he could earn from gambling. First method I find harmless, other can have consequences. But in general you can teach your kid everything and anything. It is all up to you and what kind of example you will shot to them. In fact, it is not always to educate children, but better to educate yourself, as they will be like you anyway. Always start with yourself and they will be your copy.
It's pretty normal for children if they also do what they see in their parents, that's the nature of children so as a parent, we should adjust ourselves and limit the things we do once they are in front of us because they don't know the things that shouldn't be imitated because parents will serve as role models for children until they grow up. if they see what you and your spouse are doing, they can imitate it while they are young, not unless you explain every detail of what should not be imitated by children from what they see in their parents.