Except, the thing is, a decent portion of the population enjoys throwing money away in casinos. If they feel a similar level of enjoyment/entertainment from this type of market, then it's no different and they're playing for a non-financial purpose that your calculus isn't pricing in. Maybe a stretch but theoretically, if they enjoy it enough, it can serve as a much cheaper alternative to a casino and thus could actually have a positive net return to one's personal finances even while losing.
And, I'm not even contemplating gambling addiction. There's a huge market of people that just go to Vegas once or twice a year and come home thousands of dollars poorer. But they don't need it, they may not gamble outside of Vegas, or nothing that would signal an addiction.