As @rolfedh mentions:
You are comparing a work from a publishing house with works from Kindle Direct Publishing. Different content sources = different legal contract.
Amazon seems deliberately vague to help bolster its position on accepting or rejecting KDP works:
Original Wording 1
"We don't accept pornography or offensive depictions of graphic sexual acts."
Offensive Content :
"What we deem offensive is probably about what you would expect."
[W]e reserve the right not to sell certain content, such as pornography or other inappropriate material.
Offensive and Controversial Materials Guidelines
This includes titles, cover art and descriptions as well.
Regardless of the vagueness, the clear intent of the KDP guidelines is to weed out a flood of cheap pornography, as well as deliberately vile books, and at least keep the "erotica" more tasteful by avoiding taboo or "illegal" subjects such as incest, rape, bestiality, underage sex, etc. (and thus keep Amazon less liable to prosecution)
Also, there is the small matter of who (originally) is publishing the book. Amazon potentially assumes more "risk" from a legal perspective (monetarily, prosecution for obscenity, etc.) by being the primary publisher via KDP. Thus publishing via KDP is likely to be more tightly controlled.
But the "Song of ice and fire" seems to violate every regulation, is it still not a problem for Amazon?
This is a bad book to compare anything to:
- It isn't published via KDP, so yes, those particular rules don't apply.
- Amazon is not the primary publisher (and it is published by a larger company Amazon is unlikely to be able to bully too much).
- It clearly isn't pornography (or even erotica) in the "traditional" sense (arousal isn't the main point of the book) and thus likely fairly immune to obscenity charges, etc.
- The book is already worth about a bazillion dollars. This gives it special consideration.
So does the axe swing for just small houses and self publishing authors?
The key here is legal action for the work.
To reiterate, if Amazon is partnered with a larger entity (publisher) and are sued by a third party, they are less likely to be as financially or legally liable in court since they have a large partner. And if things go badly with the book (obscenity charges, recovering money for books that incur other costs for some reason) perhaps they can sue the original publisher to recover some or all of the cost.
Small houses/individual authors don't have "Amazon" money usually.
So a pseudo first time publisher is different from an actual publisher (or house) that exists outside of Amazon (no matter how small )?
Yes. But even a small "outside" publisher is still unlikely to get the full benefits of consideration a larger publisher might, especially via legal contract.
Note too, as mentioned, using KDP Amazon is essentially replacing a traditional publishing house. But even with a regular publisher, Amazon can of course "reject" that material simply by refusing a contract to distribute the work.
1 Original (Non-Updated) Link