When the United States was a developing country, it had no restrictions on child labor, minimum wages regulations, or mandates regarding safety in the work place. So be it for the US to pass regulations that tailor to those ideals, as they are not necessarily bad ideals. But to expect other nations to abide by those same ethics is disingenuous and only puts our nation at a disadvantage to other developing nations who are willing to forego any such regulations for the purpose of keeping their labor costs down thereby making their country more affordable to do business in.
It is unethical for developed countries to impose sanctions on countries who are doing the exact same things the already developed nations needed to do themselves to become developed nations. Secondary to being unethical to impose sanctions, it is also an economic policy that is disadvantageous for our own country because it then raises the cost of living for everybody in our country because we are forced to buy from nations with higher labor costs, and that translates over to higher prices on everything.