You can of course consider the money you lost as the payment for the fun. Like going to play arcade games for example.
But trying to recover the lost money by gambling more is probably one of the worst things you can do while gambling. It's a downward spiral from there.
The problem is, the "fun" part of gambling is the expectation of winning. Sure, there are some other factors, such as drinks or social interactions in brick-and-mortar casinos, but I can't imagine many people would bother stepping into a casino (or logging in) if they knew
for sure that they will end up losing.
So gambling is not quite like other forms of entertainment and you can't really separate the "fun" part from the money.
And, what's funny, most people would probably feel much better if they drank away $200 in a bar with their mates, rather than losing $100 in a casino. Because losing always has some negative emotional load.