That page describes how if you are using Ubuntu, you need to make sure your graphics drivers are up to date, because Ubuntu doesn't always have the latest drivers.
It says nothing about Proton only being supported on Ubuntu, its just telling you how to properly set up Proton, on Ubuntu, depending on your hardware.
I'm not arguing with anyone, I am correct, you are completely wrong.
Though I guess now I understand how you came to be misinformed:
Poor reading skills / lack of knowledge of some intermediate level tech vocab.