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.
Wasn’t the matte option that disappeared just then removing the glass in front of the screen? I seem to remember that (my MBP from that time was glossy).
The nano textured coating they are using now is quite complex and I am not quite sure it was applicable at such scales cheaply enough back in 2015.
A glossy option was introduced in 2006, but the MacBook Pro was still matte by default.
In 2008, the MacBook Pro case was redesigned, and then the display situation changed significantly.
> “…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.
A sentence in a PR that highlights an indisputable advantage of a glossy display does not position glossy as being superior overall but merely superior in the respects mentioned, which is not controversial.
Moreover, Apple continued to offer a matte display in the MacBook Pro for years after that PR, so why would they sell an "inferior" option?