But a much easier argument against sports betting is that it ruins the sports. Players throw. They get good at subtly cheating. The gambling apparatus latches itself to the sport, to the teams and players, the umpires and judges, the sporting organizations. With this much money on the line, it's not a matter of if but when games are thrown, cheated -- the bigger the game, the bigger the incentive. It's even easier now because of the amount of side/parlay betting that is available. It exhausts the spirit of competition.
Sports gambling is diametrically opposed to sport itself.
I'm not putting up a straw man - I'm actually in favour of it. I agree that all forms of gambling ruins lives. We would improve society if we agreed that all gambling is bad.
As a professional gambler (aka farmer) I understand I am biased, but I have a hard time squaring that society would improve if we all agreed my gambling habit is bad. Especially if that means going as far as a ban. What would people eat? If you think Mother Nature is going to give up her bookie position, you're wrong.
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.
In the narrowest view, sure. But, for example, not all casinos, hell not even all machines in the same casino, offer the same odds. What about the work you put into determining which machine offers the best outcome? Is that not a skill? Obviously you can just sit down at any old random machine and see what happens, but that's the same as your "zero skill" farmer throwing some uncertified seeds on the ground and hoping for the best. In both cases there is an opportunity to improve your chances of success if you so choose.
Some aspects of farming lean on skill, but other aspects are pure chance. "Pull the lever and wait" is often all you can do. I'm not sure you are being fair in diminishing slot machine playing down to just one event, while happily considering farming as the sum of all its events.