Gambling is no scam because you are aware of what you are doing or game you are playing, in as much as there is an agreement by the two individuals or groups before starting the game or bet it is not. But when you say scam ,the person is not aware of your intention .
Gambling is a game of try your luck ,a game of chance if you can win to make more money or valuables for yourself, getting rich quick.
Gambling cannot make anyone get rich quick because it's a game of chance. However, there are few persons that was able to hit the jackpot but most of them don't use to be satisfied with such a big amount. For that reason, they will continue gambling and hope to win more but will later end up gambling back all the money to the casino. Nothing is scam in gambling, only if you use a scam casino.