I agree that stopping your addiction is actually a choice but the problem is that the choice is really hard to make and its not that they don't actually want to stop or they don't know that this act can destroy them, its just that some of them lack the will power to actually stop this habit because an addiction is really hard to stop especially gambling and drug addiction and most people are even an addict of both.
It's because they don't want to kick the addiction and are too comfortable with it for it to be difficult. If they want, they can ask for help from other people to help them create new habits and accompany them so they don't feel alone. After all, when we lose, it makes us feel annoyed and there is a desire to recover from that loss, which can make us come back to the casinos and gamble. We hope to recover from those losses and also get wins and that's the beginning of a gambling addiction that we may not even be aware of.
It's one thing to be very conversant with something but a totally different different thing to be an addict of something. In reality, they have similar attributes but the later is more difficult to let go than the former.
It's very difficult for a gambling addict to wake up one morning and say that he's not gonna gamble again. But I think the best way to help an addict is to get a therapist who can help in talk him/her away from the addiction and also proffer other meaningful things he can do apart from gambling