Maybe setting a limit on the amount of money spent on each person who gambles will help a little to keep gamblers from spending money they can't lose on gambling, some regulations must be detailed and able to minimize the risks that may occur when gambling is legalized, because it will definitely get a lot of consumers.
I don't think it's complicated though, government could have done their study on whether legalizing gambling is going to be good or bad. And in this case, I'm inclined that they did see more pros of it that's why they approved. And perhaps they have steps or plan already in place if ever there the number of gambling addicts are going to increased. They will have to build rehab facilities for that.
It's already has a stigma, but perhaps the money that they can generate thru gambling is very big that Thailand is really willing to go 100%. And the government should be in top of everything here, in my opinion and again they have contingency for such disaster and maybe all corners have been covered by them and that they are ready to embraced all the stigma and negativity that will come their way.