I think it has more to do with the fact that there is a little more "skill" involved in sport betting than in other forms of gambling which usually rely purely on "luck"... like dice, roulette or slots... Blackjack is a bit of an exception, but only really in live games where the decks are not shuffled every hand.
But I digress... with sport betting, you can do a lot of research and analysis and make fairly good judgments about who will win and who will lose... of course, there is always an element of chance (bounce of the ball, bad call by referee/umpire, unforeseen injuries etc)... but by being informed and having a good understanding of the game, the competition and the teams/players involved, you can really get a lot of results correct...
however, this is the reason why a lot of the payouts for sports betting are so much lower and not as "attractive" to some gamblers... winning @1.05 on a surefire bet doesn't seem great compared to getting 2x payout on dice... but a 5% instant return on a near sure thing isn't really all that bad...
At the end of the day, sports betting comes down to you vs. the bookie... it isn't just mathematical chance and probability...
Very well explained HCP. I use the term
advantage in defining it. In sports betting, you have an advantage when you have a background of how the team plays or if you know what are their stats on that sport. At least with that, chances of winning will be higher though it's still not guaranteed.