Sadly a gambling addict doesn't understand what's self control and discipline, he will try to gamble as long as he have money and will try anything to get money. If every gambler understand about self control and read every warning message on the casino, there will be no gambling addict.
Actually all of us know and understand about it but in certain circumstances, we took the wrong decision due to some reasons such as stressful or greed.
Before they are addicted, there is a process and all of us start with the same but in the process we may take different action.
Those who are addicted are those who take the wrong decision by ignoring their self control.
I think they're born to become gambling addict that used to make the casino's owner become rich, make a debt collector to work etc.
Absolutely there is no one who is born to become like that, it is all about freewill, and addiction is the effect of the freewill taken by people.
And there is no one who want to be born to become addicted, not only gambling but also in other things.
If you say that they were born to be addicted, you are blaming the God who create us.