Why shouldn't children work at such a young age?

They need proper education, without proper education they may never be successful in life. They could also get hurt or be exposed to harmful substances such as pollutants, metals, dust, and just about anything in a factory. Being exposed to these things could cause serious medical problems. Also, you could look at things in a psychology way. The children get used to working and never decide to try and better themselves because they settle for just "good enough". Therefore, they might not ever live up to their potential and may live an average life, with an average paying job, and have an average car you drive to your average house in your average neighborhood. Hopefully this isn't too confusing and helps.