Are you arguing in favour of storing a nominal datetime without additional information that allows it to be resolved to an instant in time in those cases, or are you just debating the nature of that extra information?

If the latter, we don't disagree. There's more than one way to do it and plenty of use cases with special requirements (though IANA timezones are sufficient for most purposes). If the former, we profoundly disagree and if you are a professional programmer working in a field that makes significant use of times across multiple regions you will create misery for your colleagues until you change your approach.

But you will at least be far from alone in doing so...