My theory, based on research in social psychology, is that the infighting surrounding Atheism & Skepticism is a clear indication that intelligent design/creationism is no longer a serious threat.
Essentially, Atheism and Skepticism do not completely overlap in terms of philosophy or goals, but joined forces to defeat the real threat posed to science education by intelligent design/creationism. The likes of Eugenie Scott and PZ Myers joined forces to slay that dragon. Now that the dragon is dead, they have turned on each other.
Bear in mind that I’m not using that Scott and Myers as proxies for their respective groups and not really describing their actions. Well, at least not for Scott.
I would like to take this moment to congratulate Eugenie Scott for winning.