For what it's worth, the title did confuse me. What the author seems to mean is audio files as opposed to physical media, not the MP3 format in any specific way. I thought it would be a technical discussion of the MP3 format when I clicked the thread. Your example seems much harder to misunderstand in typical contexts so I'm not sure the comparison really works.

(Then to add to the confusion, the article starts with: ``by “MP3s” I mean any fixed digital documents of audio. So, by “MP3s,” I also mean WAV files, and FLAC, and ALAC, etc. Actually, I specifically don’t mean WAV`` err so what's it gonna be...)

Of course, I do see your point in general. It's like cryptography vs. cryptocurrency (crypto=?) or some people objecting to the media's use of the word "hacker" to mean "criminal as applied to the digital domain". Those battles are lost and that's just how the language evolved: everyone knows that crypto in an investment context doesn't refer to public key encryption and that hackers on the news don't mean painters (reference: http://www.paulgraham.com/hp.html). But for MP3s, in this particular case, I think the author caused more confusion than clarity.