I always thought of stock-picking as something that the average Joe should be careful with. Trading on less information than insiders and slowly being eaten by fees and taxes. It's an under EV game.
Besides that there's the wisdom of crowds that will eventually follow the trends and invest irrationally (pump and dump). That's how bubbles are created.
Every day I would log in and manage my account - I was a commodities broker and I managed to build a pretty powerful little empire with my savvy transactions.
While not as powerful when it came to ore... my wheat holdings were no laughing matter... that was until the day I smoked pot, dialed in and accidentally sold all my wheat holdings as opposed to buying up all the other supply - thus eliminating my monopoly on the galactic wheat trade...
Man, Trade Wars was a blast in the early nineties.
But on the other hand I'm sure there are a whole lot of young people on the other side of things. Those who start learning about stock-trading and soon see it as a way to make money fast by taking huge risks. They get spammed by 500$ signup bonuses to various stock-trading platforms, they're presented with 100x leveraged trading options and such. I don't see much benefit in that.
What I think is young people should be taught how the market works with a huge grain of salt. Definitely not by letting them go wild with play-money since we all know what will follow up.