Publish For Pay Restrictions

I published yet another book in Smashwords. What to my wond3riing eyes should appear but a requirement that I have to swear that my latest book doers not contain any incest or pseudo incest.
Zombie sex, okay. Sex with alien slug creatures okay. Incest, not okay.
(Don't ask, I just work there.)

This was discussed on the forum a while back. On 16 August 2017, B&N sent out a memo on pulling books containing the following (and other unspecified categories): "works portraying or encouraging incest, rape, bestiality, necrophilia, paedophilia or content that encourages hate or violence." Smashwords using B&N as one of its major distributors and was told to do the same or B&N would pull the Smashwords distribution account.

Actually, Smashwords doen't care, but if you want to have them publish in the Channels, Sony, Apple, B&N won't take those books.