You're asking the wrong question, in a free society (supposedly) people are allowed to do whatever they want by default. They're not perimtted to do things, they're forbidden from doing specific things.

Is gambling a neg-negative? why do you care? how is that relevant? Things shouldn't be forbidden because of net impact, specific harm needs to be outlined and addressed. Most of the time, there are more specific problematic behaviors that should be legislated against, not gambling.

In your example, that person spending their rent money could maybe addressed by the law? Or if someone spends their family's savings on a bet, that specific behavior can be addressed. If you think about it, this lazy approach doesn't address root causes. Maybe that guy's rent money, or family's savings, he could have blown it on a fancy car, no law against that.

Conversely, what if someone bet all their money on a stock option? People kill themselves over this, but it isn't illegal. you see how the entire approach is crooked and lazy? categorizing "gambling" addresses the reactionary emotions of the crowd, it doesn't address root causes, it doesn't evaluate nuanced situations.

It isn't betting or speculating that is the problem.