Yes, it is, because in your phrasing the fact that nobody else keeps time that way is the cause and lack of support in software the effect. The comment that I originally responded to is phrased as though lack of software support is the cause of weirdness.
I object to the latter since software is not the source of truth, the social practices it aims to encode are. It is perfectly reasonable to say that this particular practice is so rare that it is out of scope, but this makes tzdb a not quite correct approximation of reality, rather than reality an approximation of tzdb.
