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.