Author of the article is the artist for the Pepper & Carrot webcomic.

TL;DR:

The reason seems to be due to the branding on the open source drivers.

Wacom has been sharing their specs with open source hid/input driver teams for years. Because of this most projects are named something to the effect of libwacom or wacom-hid-descriptions despite including support for Dell, Gaomon, HP, Huion, XpPen and more. Because repositories are named after Wacom rather than something more generic other brands don’t want to share their specs with something branded after, or with a competitor.