When we are doing something that we know is not incorrect or immoral but that we know other people may consider it to be the case then it is better to keep it a secret, as if you tell someone about the fact that you gamble and then that person tells to someone else you could easily end up facing some issues you never wanted to face with that person, however slowly but surely those outdated ideas against gambling are being left behind as gambling becomes more popular.
The right and wrong thing was based on the individual,some things are correct to some person.The same thing was wrong to other set of people,hacking was the illegal and unethical one.But to the hacker,the same was ethical one.Because they earn using the hacking,it was their own profession.The gambling itself not an ethical one to the Islamic community,other community people will try to use gambling as the real profession.So everything will be differ from person to person.If you are from the Muslim community,you can do the gambling with secret.Because the people from your community will do criticise your playing in the gambling.