Why focus so much on individuals? Look at the countries where gambling is 100% legalized, such as Macau and Monaco. These countries have become super-rich due to the tax revenues from casinos. Also, huge number of jobs are created as a result of gambling.
Yes some countries have legalize gambling, but still they have restricted the under age people from visiting casino and play gambling there. I think t hat it is a good decision it can prevent young people from wasting their time by visiting casinos.
SOme countries want revenue but some countires want to save their tradition they can make money in some other way than ruining the people's life too.But most of the people playing in that country were foreigners so it is like a visiting spot so it is not fit for all the places if they want to create jobs and revenues there were lot of ways also available.