Betrayal, a form of

Betrayal, a form of deception or dismissal of prior presumptions, is the breaking or violation of a presumptive social contract (trust, or ...

I don't believe Asus ever betrayed GNU/Linux. In order for Asus to betray the GNU/Linux community, Asus would have to first join and become an active participant of the GNU/Linux community. I think you are mistaken to presume that Asus became an active member of the community simply by making use of GNU/Linux.

I believe that Asus took a GNU/Linux system and used it as the software system in their computers. Asus used our free software systems to help sell their computers and there is nothing inherently wrong with that. I have had no recollection of Asus ever making any commitments to our community other than doing the minimal amount of licensing requirements of the various software. I believe that Asus never intended any meaningful relationship with our community simply because it didn't make any real effort to cooperate us. As far as I recall, it was the GNU/Linux community that made noise about Asus's system choice.

With all this in mind, it should not come as a surprise when Asus decides to let go of their GNU/Linux variant when there is a change in the environment (Microsoft allegedly making deals to get them to forget/demote GNU/Linux).