I think it depends on how much money they are playing, so let's say they are saying it's only for fun, leisure, and they are really spending an extremely small amount of money, like money that they can afford to lose, then for me it's fine. If that is their goal in playing/gambling, even lose or win, that's fine and acceptable.
You are right, but don't forget that losing Small amounts of money constantly for a long period of time can accumulatively be a huge amount. I used to have fun when I gamble with an amount that's within my capacity to lose but after a while I decided to do a little addition on those losses and I found out that it was a huge amount, at this moment of realization it didn't feel like fun to me i started having some regrets