I think we are largely in agreement about your main contention. You have repeated one point with which I still disagree. Whether a word is jargon or not is irrelevant of its usage, so I still disagree with your statement that “metadata is jargon when it is used imprecisely or to feign precision.”
The precise definition of jargon is ”special words or expressions that are used by a particular profession or group and are difficult for others to understand”. I don’t dispute that it has the connotation you mention, that people prone to use jargon often do so exactly because it is “difficult for others to understand”. I just think that reserving that term totally for that one negative class of use robs us of its positive uses, as well.
So metadata is jargon whether it is used in the way to which you object or in the way I have also seen it used, as a way for non-bogus techies to speak in a more precise, condensed fashion.
Maybe I am being pedantic and unproductively so. It seems similar to me to the various usages of hacker and just as unlikely to be resolved unambiguously. Maybe since my view seems to be in the minority, I have to live with constantly explaining myself when I use the term, jargon, non-pejoratively or just learn to let it go altogether. Doubly so because I will be the first to admit that the instances where jargon serves as well as or better than simpler though less pithy explanations are increasingly rare.