Who's protesting military rule in Egypt?

"Although the demonstration was originally called by liberal activists..."

... most stayed away after it became clear that the Muslim Brotherhood and other Islamist political parties would dominate the day....

The spark for the Islamists’ protests was a recent set of declarations issued by the military-led government as ground rules for the drafting of a new Constitution. Many of its provisions sought to enshrine protections of individual liberties and minority rights that liberals have sought. But another provision granted the military a long-term political role as guardian of “constitutional legitimacy,” which many Islamists suspect is a reference to the secular character of the state and could give the military an excuse to intervene at will....