Another reason that trading is not the same as gambling is because in trading, everyone sees the same information... chart patterns, level 2 quotes, time and sales, news sources, etc..
People act on the information differently, but the information is available to everyone to make a bet on future price movement.
Take a pro poker player and a professional trader, and I bet the trader will have more up days than the gambler.
Even the "money management" in poker is skewed. If you want to raise, how much should you raise by?.. and if someone raises you, how do you know if that amount is over priced for the cards in your hand?
in poker, there isn't really a way of tracking other players performance other than by looking at their stack over time. Unless you're some MIT brain child and can chart all this stuff in your head. Every hand is random and so are the actions of the players, but in the market, there are many, many predictable situations both before and after the event has occurred.