> Lifting sanctions just helps the mullahs flex their power on Iranian civilians

I am not sure how you're imagining this. Showing that they can buy an American iPhone, for example, is a worse "flex of power" than killing 30k protestors? I just don't get what is the supposed power flex without sanctions gonna be.

The purpose of sanctions is (everytime) actually different. It's to break the civilians so they would revolt against the government. So with sanctions, you're hurting civilians by definition. It might be "for the greater good", but it's certainly amoral approach in my book.