Gambling is not something that is by itself wrong its just that people are doing it wrong in my eyes, I think that some people are just also making it bad and wrong.
Gambling is something that can be fun and enjoying so long you are not doing it for the profit.
Gambling itself is not wrong. That is why a lot of country allow casino to be setup. Otherwise it will be totally ban like weed or other drugs. However, casino does give a lot of social problems as people tend to overexert themselves when gambling. These people give casino a bad name.
Right, gambling is not really wrong but what is making it wrong are people who are not using gambling at the right use of it and they are making themselves addicted to it.
So out of their misuse of gambling they are the ones who are promoting gambling as wrong because the result of gambling to their life is making them lose all of their money.