I don't agree with the analogy, but let's run with it for a second anyway.

Sending a mangled `text/plain` part in a `multipart/alternative` (when you could simply omit it) is the email equivalent of having a store that advertises that it sells Amish-compliant items, but the only compliant items on sale are hand-painted wooden boards that say, "Sorry, we don't sell Amish-compliant items."

Don't want to go out of your way to cater to the Amish? No problem. That's not what the post asks of you; the post simply asks you to stop claiming to do so.

And yet why are people going out of their way to send multipart emails with useless parts? Your analogy does not fit as the Amish person is potentially refusing the HTML part: I just cited my preference, confirming to the protocol, and am being actively sent garbage information as somehow someone seriously thought it was easier for them to go out of their way to give me the option and then laugh at me for making the wrong choice than to just send an email that is HTML only.