I'd probably take the more charitable view that usage of the phrase in the negative is a willingness to embrace the spirit of the saying rather than attribute it to a misunderstanding.

If it is a misunderstanding, that is. While all sources I've seen sdo agree the phrase is of military origin, the Ngram shows usage as early as 1908 [1], with usage between 1930 and 1955 in English fiction [2]. Maybe the origin of the phrase predates the pointless numbered hills of the Vietnam War, and perhaps those hills had value and were worth dying on.

Not that this is a hill I'm willing to die on, though. All I wanted to point out is that the opposite phrase is used often per past experience, and Google Trends [3]. I can't actually find any trend data for the "original," but it is used.

[1] https://books.google.com/ngrams/graph?content=hill+to+die+on...

[2] https://books.google.com/ngrams/graph?content=hill+to+die+on...

[3] https://trends.google.com/trends/explore?date=all&geo=US&q=w...