"Because most of them have no idea just how grim the life of a subsistence peasant farmer is"
You could say the same about oil rig workers or coal miners and they are going to use both coal and oil when they grow up. Should we teach kids how to do these professions too? Where should we stop? There's many "grim" professions, things that need to be done in life, yet school kids are usually shown none of them. So what?
Agricultural produce is a strongly limiting factor on how good human life can be - the most important process we run. To give kids a rudimentary insight into the mechanics and economy of it is - to me - clearly a more important lesson than understanding an oil rig.
I don't disagree - but energy, mining, and forestry are also fundamental parts of the economy (with transportation, construction, and manufacturing on the level just above those), and if we're talking about giving kids a rudimentary insight of the mechanics and economy of this big system in which we all live, I don't see any reason to stop at agriculture.
They don't. As I mentioned earlier - high-yield industry scale farming might be evil, dishonest or capitalistic. Doesn't matter - it is what allowed us to not be farmers. Few hundred hears ago you had to be a farmer to survive - today you don't have to, because there is enough food for everyone on the market. IF you can find another job, that is. But if you find a different thing to do, then you don't have to be a farmer, you will be able to buy food.
High-yield farming also isn't any of those things. There's a difference between outcomes and practice (or indeed, general American administrative incompetence).
You could say the same about oil rig workers or coal miners and they are going to use both coal and oil when they grow up. Should we teach kids how to do these professions too? Where should we stop? There's many "grim" professions, things that need to be done in life, yet school kids are usually shown none of them. So what?