Well, it depends. If the kid is doing work that is worth 2 bucks an hour, it isn't stealing. If the kid is doing work that is worth thousands or millions of dollars, and the grocery store more or less tricks or colludes to keep that money for themselves, then that is quite clearly morally wrong and the equivalent of theft.
This is a flawed example, because it doesn't exist in the real world. Not in a market economy, at least. There is nobody doing work with thousands or millions of dollars (depends on over what time frame, obviously) and getting paid $2/hr for it, or anything remotely close to those figures. It's like saying "Yeah, but what if there were a square circle in this conversation,
what then?"
I don't have a moral leg to stand on when it comes to prohibiting kids from monetizing their NIL, but that's completely separate from the question of whether they were ever being stolen from (and whether I like it or not, and think it will be disastrous for the sport). And I haven't seen a compelling argument that kids were ever being stolen from.
I don't buy the argument that colleges successfully monetized the sport, because academic curricula have effectively been monetized too, and for way longer. All these engineering and medical nerds, etc.....they're the reason why schools get ridiculous amount of grants and other forms of government-backed funds. The schools literally made billions off of academic kids and nobody ever made the argument that they were being stolen from. By the same token, we shouldn't accuse schools of stealing from kids because athletic students didn't get paid to play their amateur sports. Hell, even the REC leagues in Baton Rouge make money.....nobody ever paid me to play basketball in them when I was a kid. And nobody "stole money I earned" either.