If you think about it, D'Souza's position is simply a more in-depth restating of President Bush's "It's a religion of peace" rhetoric. Certainly, D'Souza deserves no less and no more criticism than the President himself. He's trying to prevent a global war by making friends out of enemies. I don't know how effective it will be. As the old saying goes, it may be black, but you can't polish a turd. The "Islam and the West have a lot in common line" requires a lot of suspension of disbelief, perhaps too much to actually get off the ground.
I should have said 'inexplicable (to me)'. I'll have nothing to do with whitewashing evil when and where I find it, nor will I keep silent when I see such whitewashing being attempted.