The fact that the bad policies of North Korea lead to bad economic outcomes is no evidence that all bad economic outcomes are due to bad policies. It simply isn't.

Nobody in the EA camp denies that policies of countries matter and that the property rights and the rule of law aren't important. I haven't seen Peter Singer argue either that putting Embargos on other countries to put economic pressure on them instead of engaging in trade is bad.

Most African countries on the on the other hand don't suffer under strong embargo's. They are in the sphere of the IMF who preaches property rights for decades and tries to get the countries to respect property rights.