You're not playing the "cite a definition" game correctly. You neglected to include the reference to the presumably-a-dictionary you used. How am I supposed to go back to the same work, cite another subdefinition that has about a 50-50 chance of actually applying, and then argue that I'm correct while simultaneously invoking some half-assed "Amazon is really a newspaper, or maybe something involving cars" metaphor? The Internet has a well defined protocol for this dance!

Anyhow, trying to shut things down by definition only works in mathematics. Redefining away what Amazon as "not censorship" won't mollify anybody, as they can still choose to be legitimately annoyed at the perfectly legal and arguably perfectly ethical actions Amazon have taken. Acting legally and even ethically doesn't mean you have the right to not be criticized.

And, seeing as how if this is "not censorship" we don't actually have an English word for what it is... yeah, it's censorship. It's not government censorship, but it's censorship. It's also a sufficiently different kind of censorship that simply knee-jerk applying our attitudes towards government censorship may not be relevant, but English simply doesn't have the granularity to deal with this. That's OK. Everything works that way anyhow.