This doesn't happen to strickly phones, if you are such a white knight about this topic, there are A LOT of things (mainly technology based, like TV, computer components and such) have the same issue, you better look at each computer components you are using and where they source their factories. Clothing is another thing, a lot of brand will have factories in China and have the same issue, some are reported for and ignored (people prefer their clothings to stay cheap), some are just never reported.
You can be a white knight in this case, but if you are ignorant in other cases (clothings, other technology gadgets), you are just as ignorant as the one you call ignorants.
This world will NEVER be an ideal world, until the country is developed things like child labour will always happen, Europe and US had their fair share of slavery and child labour back in the days, we just came out of it once we are developed, same for those countries, they just need to get out of that era first, until then, it is the norm for them, thinking you can just change it all by protesting against it or stop buying iPhone is just silly. In fact, those children can now at least have a meal, if the Apple now stop using them, unless the factory find itself another client, the child is making NOTHING and is going to starve.
So until then, I will play with my gadget in ignorance, get fat and die stupid, but I am happy.