I get your point and if you ask for my opinion I will also say same thing but I think most western culture or way of life are ignorant of some of these things as the world with them have become so free that the children are constantly exposed to such habits even without the consideration of the effects(negative) that can get to these little observers. Although I know that human are of different types as some are ignorant and careless and do fall under this category.
Restricting what your children could watch was easier decades ago, because back then kids had very little access to technology and at most only their friends could expose them to gambling early on.
However thanks to the internet not only kids are exposed to all kind of things at an inappropriate age, now parents are not even aware this is happening as it is impossible for them to monitor everything that their kids are doing online, since it is often the case that parents are way behind in the use of new technologies compared to their own kids.
I admit that limiting viewing for children is very difficult because nowadays, children are used to watching shows they can easily access. With more advanced technology today, they can choose what they want to watch and even do it without the help of their parents. This is where parents supervise their children to be able to tighten their rules towards their children so that they will not be influenced by anything they see. Husbands or wives need to know this so they can think about whether they should reduce their gambling activities for the sake of their children and maybe stopping gambling is best for them.
This is not a matter of who should stop, but it depends on each individual's awareness, husband or wife because this is their responsibility. If they could realize it, they would think that they both need to stop gambling.