I don't really know what people mean when say they are gambling for fun, there are many places that one can go and have fun maybe going to cinema with your family.
Gambling is mostly for the rich and if you should win at time you also have to take some big risk if you win you know you win if you also loss you know you lost as long as it's the amount you can let go, you can't be struggling to feed and you are addicted into gambling you will hate your self most person don't have any source of income and they are gambler claiming they are gambling for fun when you are slowly losing money each day, gambling shouldn't be seen as a source of income.
Since you consider gambling is only for rich, how it comes that you don't understand what people mean when say they are gambling for fun? You can consider it as rich people having fun trying their luck in gambling.
Whatever, i don't agree with you saying that gambling is only for rich. We don't have access to statistics about financial conditions of gamblers, but i am sure most of them belong to middle class, despite a just a little percentage gamble just for fun as the majority play with more money they can't afford to lose.