I agree that people can't learn everything about every market. But what people care to learn about and pay attention to counts for something.
Imagine your friends are trying to decide on a place to eat. You suggest a very healthy restaurant where all the food is listed with ingredients and their source farms. But then someone says, "Eh, I wanna save money. Let's do Taco Bell." You explain that that's an objectively worse decision. That food health is really important. That in the long run, eating unhealthy actually costs more in medical bills. But they decided to go to Taco Bell.
Putting your foot down and demanding the healthy option might objectively be the "right" choice. But in reality, they'll just get Taco Bell on their own time and resent you for taking their choice away. People have to be presented with the information and decide for themselves or they'll just resent the institution enforcing the choice.