As you go on to say, it's a mess. However, given that it's a matter which impacts importantly on the general population, I think that one really has to visit the question of what terminology really should be regarded as 'correct' - that which is probably believed to be correct by 95%+ of the population, or that which is probably believed to be correct by <5%. Language, including terminolgy, is, after all, about (or meant to be about!) effective communication.What majority of the population getting something wrong determines it then be correct?
As I said before, just find me a few members of the general public (who haven't visited electrical forums!) who think that 230V is 'low voltage'!
However, I certainly agree with you that to 'accept' an ambiguity as to what, say, 'low voltage' means would be unacceptable, and I can't see the 'official' voltage bands getting re-named/re-defined. Hence, having got ourselves into this mess, I think that the only solution would be to try to 'phase out' this terminolgy completely (in relation to things which impact the general public), and to encourage people only to talk about actual voltages. Merely attempting to 'educate' the tiny proportion of the public who visit electrical forums is certainly not the answer.
Kind Regards, John