The details are in the blog post. Basically, every skeptic community I've looked at has espoused the very behavior that Carl Sagan criticizes in the book. Very dismissive and arrogant folks. There's a reason he explicitly calls out the skeptic community.
I did put this disclaimer though - I don't want this discussion to degrade into a no true Scotsman fallacy:
> Or at least, visible and vocal skeptics I run across on the Internet. An argument could be made that these are the minority and not really representative of the majority of people who ascribe to skepticism.