whether poker is a game of luck or game of skill. It seems self-evident that playing poke in person involves both luck and skill. Thus, when you look at skilled players competing in a tournament, you may see that the most skilled players "won an average of more than $1,200 each per event, or received a 30 percent return on their initial investment", because they have developed strategies, have perhaps studied or memorized the odds of victory with various card combinations, and are skilled at reading the other players.
But online poker is something else entirely. If you're playing against a computer, or even if you're at a virtual table with other "real" players, you can't look for the other players' tells. And for all you know, the other live players at the table are running computer programs to analyze the game and calculate their odds of winning. Also, let's not pretend that the typical online poker player is sufficiently skilled to compete in a tournament or, were they to do so, that they would be among the most skilled.
Games worth playing include an element of skill. The rest, really, are children's games with results dictated by the roll of the dice or the turn of a card. Kids can have fun playing, let's say, Candyland, but if it can be said to teach a lesson it is one of determinism. But introducing an element of skill, even a significant element of skill, into a game of chance does not eliminate the element of chance.
I'm also skeptical enough to wonder, how often do online casino sites cheat - tell you that you're up against other "real people" or that you're in an honest game with a computer opponent, but have the computer programmed to periodically load up the computer players with "winning hands" built from cards not yet in play.