To some extent, though the committee has not moved to make this definition explicit in the standard (UB = behavior the compiler is free to assume can't happen), for one reason or another.

For the same reason that it came into the standard in first place.

No compiler vendor wanted to give up their own C variant "features".

These are all interpretations. Your trying to special privilege one interpretation by calling it the intended meaning when really it’s what I’d call an authoritative interpretation. The accepted interpretation by an authority. That doesn’t necessarily make it the actual intended meaning though.

I was under the impression the "committee" here was the people who wrote the C standard? So the accepted interpretation by the people who wrote the document must be the intended meaning, no? If it wasn't, they'd have written something else.

(Sure, it's possible they wrote something, then only later came to understand the implications of this. But the standard has been understood as allowing nasal demons since long before the latest revision of the C standard, so I'd argue that by publishing a new version without rewording that section, they're making clear that they intend its current interpretation to be part of the standard.)

It sounds like you're arguing that the authors' interpretation isn't an authoritative interpretation.

Is this what you meant?