When it comes to "earning a few dollars," those few dollars look pretty pale next to a gigantic medical bill. And if you approached any of these farmers and said, "Here's $100. Sell me your son," do you think they would take the money? But if your son or daughter dies doing the work, that's exactly what you have done. You sold your kid, cheap.
Some of this is community: A kid dies, or is maimed, and the rural community gathers round to sympathize with and support the family. They bring casseroles. They pat shoulders, and offer shoulders to cry on. And they offer all sorts of comfort and solace. This just reinforces the idea and mindset that such events are part of life, part of the agricultural life, and cannot be helped or changed. If the COMMUNITY took the attitude that anyone who allowed their underage child to work on a neighbor's farm (where they had no control over the working conditions and could not offer their child supervision), especially if that child was hurt or killed, should be held accountable, that mindset would change rapidly. Isn't that they view they would take if a 12 year old was allowed to drive on the Interstate and caused a fatal accident? They don't seem to see the comparison.
Working and learning with your family on a farm is one thing; having your child work off property requires a lot of care and forethought. And that's what these regs would have affected.