islamic democracy

I've heard the insurgents saying an islamic democracy is a contradiction while conversly many Xtns state that a democracy is impossible without a Christian base.

Why?

Is there some intrinsic understanding of what a democracy is that make one a Xtn or Muslim democracy? (o' course we have a republic not a democracy but anyway...)

There are many sects of both, won't the flavor of the democracy be what ever majority is present?

Wouldn't a 'true' democracy be the tyranny of the majority anyway? Unless the majority believes in honoring minority groups' rights?