For a couple years now I have wondered if secularism wasn't a-religious or anti-religious, but was instead the hyper-homogeneity of all religions (including non-religion); it's not that you take all of religion out of the public sphere to be considered secular, but it's that secularism is the surgical removal of all of the unique and idiosyncratic elements/tenets of each (non-) religious tradition. Secularism, then, is the universal commonality - again, the hyper-homogeneity - between all religions together and non-religion.
This thought, in some way, was reinforced as I read this question and answer post by an athiest, Bruce Ledewitz, author of the new book Hallowed Secularism. He believes, against the New Atheists who are hostile to religion, that a healthy secularism should learn from the wisdom of religious traditions. It's an insightful read, so please check it out.
Update: Andrew Sullivan discusses Ledewitz and Hallowed Secularism today.