I *have* seen groups turn MGS around. We had an AD&D 2e game where MGS player had his character eat a note we knew contained a critical, plot-stopping, clue. Pure MGS, as there was literally no reason for his character to do so. So we (other players) held him down and cut the note out of him. The GM wrote down the note's contents, tore up the note into pieces, got the pieces wet, and handed them to us.

We put the puzzle together, read the clue, and carried forth into the depths of the lair. Without "bob" and his PC.

I got"Your question comes across as rant-y. Consider rewriting it so that it takes a calm, neutral tone" -
The issue is about defending a stance, so the stance must be presented, especially since the opposite stance is more common. There are answers for dealing with disruptive players who roleplay too deeply. This is the opposite, where deep roleplay is assumed to be the norm.
An appearance of preachiness may also come from my stressing why the much-abused term MGS does not apply.
I believe that, as far as the above allows, the tone is very calm and neutral.