People's reasoning regarding this is that gambling produces faster turnaround time for results, whereas in investments, it's trickling down for a long time before you can reap something. Most people who go the route of gambling to make money wants instant result, even though that's not possible most of the time due to the element of luck and chances involved. With investments, you are slowly building something, but at least it's being build and don't have a huge possibility of being destroyed any time soon.