I don't think poker is gambling, cause it's a game of choices. I mean it has the gamble aspect cause you need to pay the buy-ins to play a game that use cards a probabilities, but it is mostly a game of choice that involves luck, like most things in life. For example, let's say you studied for a test, but you didn't give your best, the probability of getting a good grade is considerable, cause you don't know what question you will have to answer, but you studied, although you didn't gave your best. Now the guy who studied a lot and gave his blood for this test, has bigger chance to get better grade than you, cause he studied more and the probabilities to have in the test a question that he studied and knows the answer is pretty high. This is just one example, but in poker it's almost the same, the guy who studied and practiced have better chacnes of taking the best of the
hands he chose to play, but will there be hands that he know that is better to fold too. Now, the guy who didn't study and practice, will surely make a lot of bad decisions that will lead him to lose on the game.