It really depends on your definition of macro [1]. Modern programming languages like Scala, Julia, Nim, Rust etc are supporting hygienic macro.
According to D authors Mixin is not macro because Mixin still looks like D language while supporting macro would meant the inclusion of macro (hygienic or not), and depending on the implementation, most often than not will render the language unrecognizable (become non intuitive). Again if someone is purposely writing a DSL in D for generating a new language's AST then that's perfectly fine. Essentially the output is another programming language because it is the intentional product of the exercises but the original programming language is still intuitive.
I suppose you can have runtime macro like VBA but Python language designers refused to incorporate it due to issues as mentioned beforehand.
Surely hygienic macros are a subset of macros, as follows from their name?
I still don't see why D's mixins aren't hygienic macros. And the D documentation doesn't make that claim, either - it only highlights the difference with C preprocessor, not macros in general.
OTOH I can't think of anything in VB6/VBA that resembles macros, runtime or otherwise?
Mixin is not macro according to D authors. If you dig into Walter's past posts, perhaps you can find better explanations there than mine.
You can have macro in any runtime for example Ruby language, and that's the main reason for the maxim "Rails is not Ruby". That's also the reason Ruby is so powerful and to create a similar feat in Java will be close to impossible [2]. But at what cost? That's why Python now is much more popular even though Ruby is much more powerful. You can, however, create Rails clone in D language without all the macro nonsense [3].
According to D authors Mixin is not macro because Mixin still looks like D language while supporting macro would meant the inclusion of macro (hygienic or not), and depending on the implementation, most often than not will render the language unrecognizable (become non intuitive). Again if someone is purposely writing a DSL in D for generating a new language's AST then that's perfectly fine. Essentially the output is another programming language because it is the intentional product of the exercises but the original programming language is still intuitive.
I suppose you can have runtime macro like VBA but Python language designers refused to incorporate it due to issues as mentioned beforehand.
[1]https://en.m.wikipedia.org/wiki/Macro_(computer_science)