What makes the creeping political correctness on Islam so startling is its very newness. It wasn't so long ago that the right and the left both agreed that as a religion and a political movement, it was dangerously backward and violent.
From Winston Churchill, "Mahommedan religion increases, instead of lessening, the fury of intolerance" to Karl Marx, "Islamism proscribes the nation of the Infidels, constituting a state of permanent hostility between the Mussulman and the unbeliever", leading figures on the right and the left held a realistic understanding of Islam. They dismissed it as violent, barbaric, ignorant and dangerous. The right saw Islam as a threat to the Western Christian hegemony. The left viewed it as a reactionary movement of superstitious fanatics. They might praise Arab generals or scientists, but not the creed itself.
