You are 100% correct mate, a gambler cannot be addicted if he is not greedy. One of the attributes to addiction is greed and there is no way one can separate them from each other. Gamblers who gets addicted are not satisfied with the outcome of their bets and they keep on gambling because they want to make profit by all means.
Some gamblers are even making little profits but they are not satisfied with it and they will continue playing till they lose it all of it and the next day, they will continue chasing their losses.
So gambling is not suitable for such public, I will also say that trading is not suitable for them, because in this case, if their greediness is high and for this, if they lose their self-control and start taking trade or wagering based on emotions, then they are the last. It is normal to face loss. And in most cases such incidents happen more.
I would say that in order to avoid this problem, a budget or a limit should be set at the beginning that after the end of this budget no more gambling can be done or if this limit is touched then you have to take a break from gambling. And that's how I think gambling is best where you can combine fun and sometimes profit.