The reason you don't constantly see "liberals" posting about Muslims in the volume of Christianity is because most liberals aren't constantly bombarded by Islam in the same way. It's not Muslims knocking on my door on Saturday afternoons to "tell me the good news" and criticize my Halloween decorations (SATANIC HOLIDAY). It's not Muslims lined up at the women's clinic screaming at everyone who walks through the doors. I don't open my wallet and see "IN MUHAMMAD WE TRUST" on my money. So I think that's why you hear less bitching about Muslims from "liberals".
Most liberals would say all the Abrahamic religions are dangerous in that they prevent western nations from progressing into the future and achieving all that human kind is capable of. Yes, the ME is predominantly made up of backwards countries, which is why most liberals say we should just leave them alone and stop stirring up the pot. Bombing them further back to the stone age isn't going to help bring about a new Renaissance period.
So when we people are getting up in arms about Islam and the bad things associated to it in the ME, don't lose sight of the threat to individual freedom here from our own Evangelical zealots right in your backyard. Evangelicals influence US government and policy a lot more than Islam does, despite what the WR would have you believe.