I do not eat the things WHEN I am in the USA you that you mentioned...nor do I eat MSG knowingly.
Even on 'good' pollution days it is still far below a healthy level in Most Chinese cities.
Expats live there primarily for the money as you admitted...not many would do it for chump change as they would and do in nice places

People can justify whatever they wish...like a smoker saying they feel fine so the cigs aren't as bad as people say.