Of course Muslims can be "democratic." But only if they decide to eschew sharia, the Islamic system of laws that enshrines inequities between men and women and Muslims and non-Muslims. In so doing, however, they would leave that party or government open to the charge that, in rejecting or watering down sharia, they are being untrue to Islamic values and mimicking the West--which is highly unlikely to be a vote-getter in, say, today's Egypt.
The notion that a country can be democratic while hewing to sharia is either wishful thinking or specious nonsense. It's unclear to me as it may be to other readers in which of two Haroon Siddiqui is indulging.