Gambling is indeed just a game, some people believe that gambling is like investing in fast forward, since in investing there is still that we rely sometimes in luck to profit. But generally the risks in trading is quite different from gambling. In trading you can minimize risks because you can execute some strategy that can do this, however in gambling you cannot change the outcome of a dice roll.
Gambling is not a game at all. Games are based on strategies etc whereas gambling is totally dependent on luck. Indeed trading is risky but hell better than gambling because as you said, we are able to reduce the risk rate in trading by coming up with some good plan or strategy. Gambling sites should be banned.