Egyptians demonstrating Sunday against President Mohamed Morsi's first year in office waved signs singling out U.S. Ambassador Anne Patterson, telling her to "get out" and accusing her of clandestinely aiding Morsi's Islamist government. One common sign, which also appeared as a massive banner hung in downtown Cairo, carried a distorted picture of her face and the word "Hayzaboon," an insult that means "ugly old woman" or "crone."

How did it come to be that, two-and-a-half years after Egyptian protesters rallied against President Hosni Mubarak, whom President Obama eventually said should leave office, did that protest movement come to see the United States as such a villain that the U.S. ambassador is called out by name? Why is the same administration that helped push out Mubarak now the bad guy?

There are a few factors that could be at play here. A very basic factor is mistrust. Despite the fact that Egypt's protesters and the United States share a number of goals, including pressuring Morsi to show more respect for democratic processes and institutions, survey data shows that Egyptians tend to hold highly negative views of the United States and its leadership. That kind of skepticism doesn't just go away.

But the criticism seems most rooted in a perception that Patterson, and thus the United States, are helping to prop up Morsi even at the expense of Egyptian democracy. Partly this is rooted in recent history: the U.S. worked closely with Mubarak's government for years, at times pressing him for reform but more often looking the other way. But it also appears to comes from a misunderstanding of Patterson's role in Egypt. When she refuses to more roundly criticize Morsi in public comments, that's perceived as backing him. But the United States has ongoing business with Egypt, after all, and letting relations sour might satisfy protesters' desires to punish Morsi, but would be unlikely to help.

Patterson's efforts to mediate between Morsi's government and the protesters have been similarly misconstrued as an effort to impose not just Morsi's demands on the opposition, but Muslim Brotherhood rule on Egypt. Here are a few more photos of the signs against Patterson (for those wondering about the unusual spelling of her name in the first photo, the letters p and b sound very similar in Arabic):

On Friday, after reports that had an American had been killed in protests in the Mediterranean city of Alexandria, the U.S. State Department issued its strongest travel warning yet for Egypt. President Obama, speaking in South Africa, said his "most immediate" concern over Egypt's protests was the safety of U.S. Embassy and consulate personnel.