Being a gambling addict is not just about losing all your money. Some people are becoming an addict because of their winnings, they are addicted to win!
It is definitely not about some people
Unless you are a billionaire, and have been that way since your infancy (read, you've been born into wealth), you can't help becoming addicted to wins. Wins give you that supreme and unequaled feeling of being in control of your life, even your fate itself. In fact, we can call that a state of bliss or euphoria (provided you are actually winning)
So it is kind of normal and expected to become an addict of wins at almost all times and under virtually any circumstances. But the problem is, it is next to impossible to book profits in a casino all the time (which wins are about in this environment), or even most of the time for your average gambler in the long haul