Gambling isn't the only form of entertainment meant to tickle the part of the brain that craves risk. Movies have car chases. Amusement parks have roller coasters.

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.