Indeed, if trading is largely about skill and understanding the market, then why do many traders struggle to consistently outperform the market average? Isn't that indicative of an element of unpredictability and chance, much like gambling?
Maybe they want to improve their abilities, skills and understanding of conditions and situations in the market so that they continue to try or struggle. It is not gambling because they try to study every condition that occurs in the market. Even though they made a loss, they learned a valuable lesson from their last trade. They can also learn from their mistakes, which will be useful in the next trade.
But if it is luck-based gambling, you don't need to learn anything because everything will depend on your luck. You just have to place a bet, play gambling, and submit the results at the end of the game. And if you are lucky, you will win and vice versa.
So daily trading is different from gambling because there is skill and ability in analyzing trading. But if it is sports betting, they also need analysis to choose the right team.