Traditionally, Americans are spoon fed, political baby food, when it comes to foreign affairs. Mainly the lower and middle classes. What they do apprehend are human rights. And that is at the most fundamental level perceived.
When it comes to foreign affairs they normally get it wrong. Not all the time, but most of the time. The US government often camouflages the truth in order to protect American interests.
In terms of Iran and the Iranian government the American people are mainly up in arms about how free speech is being sanctioned. What they fail to understand moreover, is how the Iranian government is undivided on the issue of the election turnout. The right to sovereignty as an independent regime is a moral right.