I don't recall Apple ever "insisting" anything about glossy vs. matte. They simply eliminated the matte option without comment, and finally brought it back many years later.
If you have a reference to a public statement from Apple defending the elimination of the matte option, I'd like to see it.
To be clear, I've been complaining about glossy Macs ever since matte was eliminated, and I too purchased an M4 MacBook Pro soon after it was available.
> “…the MacBook provides incredibly crisp images with richer colors, deeper blacks and significantly greater contrast…”
This is positioning for glossy being superior.
https://www.apple.com/newsroom/2006/05/16Apple-Unveils-New-M...
The other quote is just a list of ways in which the screen is better.
It is YOU that is conflating these and saying that this list of improvements is down to glossiness, not Apple.