From what I could tell, this was a protest against the military rulers in Egypt, but I had to leave shortly after it started. I also found later on the internet, that there were people protesting for freedom in Syria, who showed up later.
A couple counter protesters (men on opposite sides) came to support U.S. military action against Iran. I think the woman in the middle was protesting against military action, and was debating issues with the counter protester.