My question back to you - is there a reason that the mortality rate of those same children in those same third world countries is so much higher than it is here???
Yeah. Low rates of vaccination, bad water, substandard access to medical care and oppressive poverty.
You don't need to look to the machete they are wielding. Child labor sucks, but honestly - for these kids its often that or starve. The risk of the machete is smaller than the risk of starvation.
Likewise, for MANY American families, the choice is "leave your five year old home alone for a few hours before you get home from work" or "not work and hope the inadequate social safety net is sufficient" or "pay for daycare and not be able to afford rent and food."
It really shouldn't be a luxury to keep your kids safe. For many people in the world, it is. Sometimes, it is astounding to me that we have the luxury to debate the ethics of what for so many people is not ethics, but survival.