Because if they were to actually come to grips with it, they would be forced to say something like: "It is obvious that Islam is a complete failure and all cultures that are influenced by Islam to any degree are terribly harmed by it. We have been kidding ourselves for the past six hundred years and living a great lie. We can no longer do this....the lie has become impossible to prop up. So, in order to make a small effort at making amends to the rest of humanity, whom we have harmed so grievously by our lies and our violence, we renounce Islam and the Koran and all related teachings. All Muslims are hereby ordered to cease and desist from reading the Koran and to burn and destroy all copies of it. Muslims are hereby ordered to discintinue any and all belief systems pertaining to Islam, and to instead embrace Christianity and Judaism as your new religions. To the World: We are terribly sorry and beg your forgiveness for our great evil."
It's very much like the inability of Liberals and Leftists to come to terms with their "religion"....to do so would be to undercut the entire foundation of their world. To embrace logic and truth would be for liberals something like what embracing the Devil would be for Conservatives....it's not gonna happen.
Seems to me that just for P.R.'s sake, they would voice objection even if they didn't fully mean it. As it is, it's obvious their gutt feelings don't match their half-hearted appologies or expressions of sorrow. It's this that makes me wonder if it wouldn't be best to start deporting some of these folks back to the camel farm.