The vast sums of money shuttled among the accounts of these young professionals — and the shocking aggressiveness and recklessness with which they played — deepened the divide between the young online players and the older guard who earned their millions when poker was still a game played by men sitting around a table. Since the rise of online poker in the early 2000s, every principle of the game, every lesson learned over hundreds of thousands of hours of play, every simple credo uttered in some old Western gambling movie — all those tersely stated, manly things that made up the legend of poker — has been picked apart and, for the most part, discarded.