I don't think gambling is wrong because in my mind , it's simply just a way to earn money or a way to relax . It's only wrong when you're playing too much and let it effect to your real life.
Nothing is wrong when we are gambling. If you're living in a country where gambling is not illegal then you are doing nothing but to have some fun or take time to earn some bucks. But if you are living in a country where gambling isn't allowed and you insist to gamble then you are a law breaker and that's the wrong thing that you are doing and you must follow those governing rules that's being implemented in your country.