Congratulations, you've committed a felony. That's what Doctorow's protesting: that Amazon forces you to commit a felony to do something as basic as changing a file format. He points this out in his Kickstarter:
What's more, Audible won't allow you to sell your audiobooks through their store unless you allow them to wrap your books in their DRM, which cannot be removed without committing a felony under Section 1201 of the Digital Millennium Copyright Act. Every audiobook you buy from Audible is locked to Amazon's platform...forever. They can revoke access to the book (they've done this with Kindle ebooks, starting with -- I shit you not -- George Orwell's Nineteen Eighty-Four... You can't make this stuff up!).
Due to the insane reach of the US and the political pressure they put on other countries, I suspect there are few countries where this specific pesky law doesn't exist.
In the UK it's only a criminal offence if it's done as part of business, or you do it so much you prejudicially affect the rights holders. This is why eg people who buy a DVD player can change it to region free mode (they're not committing a criminal offence) but the shop who sells the player to you can't tell you how to do it (they would be committing a criminal offence).
Read "F2296 Devices designed to circumvent copy-protection" and "F4296ZA Circumvention of technological measures", and contrast those with "296ZBDevices and services designed to circumvent technological measures".
There is no such thing as a "felony" in Europe. Besides, not all European countries are part of the EU, so they wouldn't share the same legal framework.
What's more, Audible won't allow you to sell your audiobooks through their store unless you allow them to wrap your books in their DRM, which cannot be removed without committing a felony under Section 1201 of the Digital Millennium Copyright Act. Every audiobook you buy from Audible is locked to Amazon's platform...forever. They can revoke access to the book (they've done this with Kindle ebooks, starting with -- I shit you not -- George Orwell's Nineteen Eighty-Four... You can't make this stuff up!).