Do we have an actual answer?

[velvetpage]

Could it really be this simple? Nutshell version: a programmer in France puts a ban on all things erotic. Except that in France, the word they use for erotic is "adulte." He understandably translated that as "adult," which put in place a code that was meant to be applied only to erotica - on 57 000 books ranging from the LGBT ones, to the sex and disability ones, to health textbooks, right around the world.

Comments

[dagoski.livejournal.com]

I know from a former employee that Amazon is or was a very Perl centric IT shop. Not only could there by a keyword mistranslation, but there could also be a Regular Expression failure that turned a minor metadata mess up into a full fledged fiasco. I can totally see this happening from my own experience trying to apply changes to a great many records in production databases. Between that and an expression that's one character too greedy, you can match way more than you intend in any filter.