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.
There's a false dichotomy between prohibition and laissez-faire, which the US seems particularly prone to. You've seen similar issues with the decriminalisation of cannabis, where many states seem to have switched abruptly from criminalisation to a fully-fledged commercial market. There is a broad spectrum of other options in between those points that tend to be under-discussed.
You can ban gambling advertising, as Italy did in 2019. You can set limits on maximum stakes or impose regulations to make gambling products less attractive to new customers and less risky for problem gamblers. You can have a single state-controlled parimutuel operator. Gambling does cause harm - whether it's legal or not - but it is within the purview of legislators to create a gambling market in which harm reduction is the main priority.
The thing that bothers me the most is that they know a lot of poitential employees have issues with the whole sector, so they try to give it a false veneer of acceptability. A good example of that was that both Paddy Power and Boyle Sports referred to themselves as suppliers of "risk-based entertainment" in their recruitment literature, something I found to be very sleazy.
I also know people who work for some of these companies and they tell me that all their talk about caring for problem gamblers is complete nonsense and that they actively seek ways to lure back problem gamblers who were able to quit.
It's also very weird that as governments around the world are cracking down on alcohol poromotion at the same time they seem to be encouraging the promotion of gambling. I would say gambling can do as much harm to a family as alcohol addiction can. I'm frankly shocked at the amount of gambling adverts there are these days. And so many of them carry the subtle sub-text that if you don't bet on your team then you aren't a true fan.
The problem is that people will gamble no matter what, so providing a safe way to do so is better than banning it. I agree with you that it's all about to what degree you allow gambling. At the very least I would ban advertising as it's effectively normalising something that most definitely should not be normalised.
And many jobs involve taking risks. Investment houses. Sales. etc. We reward those who take risks because society (often) benefits.
I find it much easier to argue against standard casino games because it's pretty easy to mathematically prove that the gambler will end up broke. With sports, it's a bit harder. As long as the vig is small enough, smart gamblers who know the teams can eke out a profit. If anything, sports gambling rewards study, thought, and focus, all things we should celebrate. THat doesn't mean I like. I would like to see it banned. But it means I have trouble arguing against it with any vigor.