That's like ~40% of the deaths in the current gaza war, except over just 2 days instead of 2 years.
Sure you will get some nay-sayers who say 'a life is a life', if moral particles existed, they might be correct.
But for some reason, humanity doesn't seem to care as much.
What makes intra-state politics more acceptable to use violence?
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.
Have we? I don't think the UN is going to invade Iran over this, especially after it went so well the last time with the US. And sanctions for Iran are already at the "you don't get anything" level, i don't think they can be ramped up any more. Morally sure, people now believe this is wrong while in the distant past they may have not cared, but practically not much has changed. The best we can hope for is an organized resistance that other large nations can funnel money and arms to.
Strongly worded letters might not mean much, but at least they are on the right side of the issue, even if only symbolically.