One of the things that's getting confused in this thread is the distinction between games of skill and games of chance. Most outcomes in life are the result of a combination of skill and chance - so there's admittedly a gradient and a big gray area between the two.

But to use farming as an example, you undoubtedly apply skill in your trade to get a better outcome. Sure, your results depend heavily on things like the weather, but someone with zero experience and skill as a farmer will have less success at it than you do. This is a skill intensive game.

On the far other end of the spectrum is the slot machine - you pull a lever and wait. Labor is nonexistent, knowledge or skill is irrelevant. This is entirely a game of chance.

So one place where we run into problems and governments need to apply some regulation is when a game of chance gets misrepresented as a game of skill, or its odds are hidden or misrepresented. When any of those things happen it means we are actually looking at a form of fraud. The operator of the game is claiming you can do really great at his game but the matter is actually out of your hands, he's lying about the probable outcome of your participation. That is fraudulent and most members of our society agree that committing fraud should be discouraged and even punished when it occurs.