Even though we play gambling just for fun, but if we count it, the money won by gamblers is still worth less than their losses. Because the casino system is designed in such a way that the odds are more likely to benefit the casino itself.
It's just that people who play gambling for fun will be able to overcome greed and only place bets on what they can afford to lose. So when they lose in gambling, they won't push their luck, or even play again to recover that loss (at least not in a hurry to do it).