Historically there was sometimes the idea that citizens are the property of the sovereign to use or dispose of as he sees fit. A lot of historical international law had the view that states have absolute feeedom to conduct their internal affairs however they saw fit.

Luckily we have largely moved past that view.

I think as a purely practical matter, moral outrage is shaped by who controls the information space. If you are a country being invaded, you probably have an organized, well funded communication department to tell your side. If you are an Iranian protestor, not only do you not have that, you don't even have internet at all because the state cut off all means of communication.