You can read his post here, or my summary below.
John points out that proponents of intelligent design argue that, even if ID is flawed, schools should "teach the controversy". And to do that, they argue, schools need to inform students as to what intelligent design actually is. "Give the students all the arguments for Darwinism and intelligent design, and let them make up their own minds" — that’s the battle cry.
Now as an aside, my point is that good sceince isn’t determined by a popularity contest among sixth graders. But that’s a digression.
John takes that logic and rhetorically asks, "By the reasoning, shouldn’t children be urged to read Why Heather Has Two Mommies and other gay tolerance books that the religious right has sought to ban from schools?" After all, if we are going to "teach the controversy" about the origins of life*, then why not "teach the controversy" regarding alternate lifestyles**?
* Not really a controversy from a scientific standpoint, but a manufactured one
** A real controversy, although it really shouldn’t be in this day and age