Interesting discussion.
I have just one comment...I've noticed a little back and forth about whether the situation of the *other* party to the gambling is relevant to the morality of a person who chooses to gamble, e.g., if the other guy is gambling with his rent money, does that make *you* immoral if you gamble with him?
I want to weigh in on the side that says, to that specific question only - no, it doesn't. First, it's not your responsibility to police the other guy's choices. Second, your choice to "protect" someone from their own choices in effect sets you as their moral judge and better - which you don't know if you are. And the more you think you're qualified to judge that, the more likely you're *not*. Third, enabling does not help to solve issues, and when you protect someone from the consequences of their own behavior, you basically perpetuate the cycle.
One complication...there are cases where the actions of the other person will damage a third party who is unable to protect himself or herself. In that case, I think it's an individual choice whether you want to take responsibility for protecting that third party from the damage. Typically, it's the other guy's responsibility and he's shirking it. Do you want to take it on for him? IMO, there are cases when the highest possible moral ground is to do so. But then, do it with your eyes open - as a way of expressing your own beliefs in terms of that third party, not as a way of protecting or taking responsibility for someone who should be doing it himself.
Mary