*goes to look at Amazon's content requirements*

"You must ensure that all Digital Book content is in compliance with our Program Policies for content at the time you submit it to us." Okay, and these are...?

"Pornography
Pornography and hard-core material that depicts graphic sexual acts."

This one is presumably what they're using to justify pulling the yaoi, although given what else they're apparently selling I'm a little puzzled as to why they have this clause in there to begin with. But there's also...

"Offensive Material
What we deem offensive is probably about what you would expect. Amazon Digital Services, Inc. reserves the right to determine the appropriateness of Titles sold on our site."

"Probably about what you would expect." Amazon, at this point I don't think you want to know what we expect you deem offensive.