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.
To be honest, at the beginning when a newbie starts gambling, he probably just tries it as fun. Some would be different, but most newbies consider it a fun pastime. But slowly they become addicted, and they don't realise that when they become addicted actually. I have seen some serious addiction togambling recently. He borrowed a lot of money from friends and family, but he really doesn't regret it. He isn't trying to return the money and just considers gambling.
I pretty much agree gambling is for rich people; whether they win big or lose big, they don't have to beg from others. They could feed their family without troubles, unlike poor addicted gamblers. Rich people won't consider gambling as a source of income; they must have other businesses to survive. However, no one can control the luck, so you have to think about it and make a strategy to manage the risk.