Or, to put it another way: any time you win a bet, you (and the bookie) are helping gambling addicts to take one step closer to "hitting bottom" and thus getting on to the first phase of recovery—acknowledging that you have a problem.

(This is the complement to the argument that charity for drug addicts is a bad thing, insofar as it delays the addict longer in the self-harming, not-prioritizing-getting-well phase of addiction. In the gambling addict case, charity would be, in effect, "giving them another pile of chips"—obviously a bad idea, no?)