I don't want betting to be illegal, but any rational analysis of it makes it clear that it is a net drain on the people involved in it, and when that proportion

I don't want betting to be illegal, but any rational analysis of it makes it clear that it is a net drain on the people involved in it, and when that proportion is large enough society as a whole is affected. The reason why there's so much fixation on sport betting in particular is partly because it is doubly addictive (because emotions tend to run high around sports, team sports especially, so even people who might not have bet in a casino might be betting on a game by their favorite team, for example). And partly because, on top of all the other problems with gambling, it creates perverse incentives for the teams to fix games.