We atheists don't discriminate against religions, we hate all of them. 
On a serious note now, there are many atheists who criticise Islam and other religions for that matter.
The reason why atheists criticise Christianity more, is because Christianity is the most wide spreaded religion at this time (though Islam is growing recently), many of the atheists used to be christians or had contact with christians.
There's also the fact that countries with christian majority have more freedom of speech than the islamic ones.
On a serious note now, there are many atheists who criticise Islam and other religions for that matter.
The reason why atheists criticise Christianity more, is because Christianity is the most wide spreaded religion at this time (though Islam is growing recently), many of the atheists used to be christians or had contact with christians.
There's also the fact that countries with christian majority have more freedom of speech than the islamic ones.
"By simple common sense I don't believe in God, in none"
Charlie Chaplin
Charlie Chaplin
