

The sad thing is, they had support for Linux in the past. And I mean not only making the launcher run on Linux, but with Linux builds of games:
OS X and Linux support
In October 2012, GOG.com announced support for OS X. They included the previously Steam exclusive (OS X version) The Witcher and The Witcher 2, both made by CD Projekt Red. GOG.com gathered user feedback in a community wishlist, and one of the most demanded feature requests was support for native Linux games, which gathered close to 15,000 votes before it was marked as “in progress”.[20] Originally GOG.com representatives said, that there are technical and operational issues which make it harder than it seems,[21] however it’s something they would love to do, and they have been considering.[22] On 18 March 2014, GOG.com officially announced that they would be adding support for Linux, initially targeting Ubuntu and Linux Mint in the fall of 2014.[23] On 25 July 2014, Linux support was released early, and 50 games were released compatible with the operating system.[24]
– https://en.wikipedia.org/wiki/GOG.com#OS_X_and_Linux_support

My point is, they should not act like Linux is the new thing they just discovered.