How many of those governments are just, however? Can you reasonably claim that all citizens consent to the policies of their government? If everyone agreed to murder you, would that make it ok? What about if everyone agreed to rob you of all of your property, your livelihood? What about only half of that? Quarter? A tenth? What's the right number? Non-consent to any degree is not morally right. In the same way, it would morally wrong for me to coerce you to pay me some arbitrary amount I come up with.