I don't particularly agree with all his reasons, but they are not likely to change. GOG put out their excuse for not wanting Linux support so they don't have to deal with this pesky request that won't go away. And if you tell them to support 1 distro, then they'll say... that's not how we do business. I'm very sure that if GOG ever decides to come back and tell you why there is no Linux support, they will use that same quote.
They are welcome to do so, but their arguments are shoddy and easy to shoot down.
Distro choice is a moot point. Look at the Arch users running Steam for linux and the games that are distributed on it. All of that possible through the "magic" of static linking,.. "magic" stuff indeed. Steam is not, to my knowledge supported or packaged by Valve for Arch and yet, there it is. In fact they licensed it in such way that people would tinker with it and make it available on their distros. By "tinker with it" I mean tinker with debs like extracting them and re-packaging them