I honestly don't even remotely understand how you got to that from what I wrote.
Unions already have a definition. You cannot go around claiming that technically unions are not unions (and that "most people don't know" this), because theory X or Y overloads the term union to refer to some unrelated concept. That's fine and well and good, within that theory, but it does not displace the usual CS definition of union. It is a load-bearing definition.
A tagged union is so called because it is a union (overlapping memory) with a field (a tag) containing a discriminator (aka discriminated union). An untagged union is a union without this tag. These terms didn't come out of nowhere. They are transparent descriptors of what's happening.
It doesn't matter whether Haskell is implemented in C or Ruby, and it doesn't matter whether it's functional, object-oriented, or a DSL for modding Elden Ring, none of this changes what a union is. I'm very supportive of type theories exploring the option space for type constructs, but someone's going to have to implement these somehow. Such as with (tagged) unions. You know, that CS concept we have, with a settled and well understood meaning.
To be fair to you, I think you're letting a very narrow definition of 'union' shadow a much more usual and common definition of the word. And that's totally fine if that's the definition pertinent to you and your work, but if that's the case, maybe don't go around pontificating about how most people do not understand unions?
