timppu: I, on the other hand, keep buying only the DRM-free games and refuse to buy that one DRM-game, demonstrating that way to them that they can't sell such games to me (because I wouldn't buy such games from other stores either, most likely).
While I understand those whom GOG has managed to piss off completely and are boycotting all their purchases here (and I do sympathize), I also believe voting with your wallet and only buying truly DRM-free games here is probably the best message one can send to GOG. Because you do get glimpses of the old GOG at times, as was the case with the recent classic Star Trek games drop and those are worth supporting.
Despite their apparent incompetence at times (at least to the outside observer), I know for sure the GOGbears are keeping an eye on sales analytics, so if nobody buys problematic games, like this... ehm... "wonderful release", they will notice and might do something about it. Or they may not. But then again releasing games which don't sell is hardly a workable business model. Boycott anything that violates the DRM-free principle and warn people as best you can to stay away.
Point being, using just the carrot or just the stick is not as effective as using the carrot and the stick at the same time. I understand a lot of people are emotionally involved in what GOG is doing (I'm also one of the early people who came here because of nostalgia, and I remember the early days fondly), but it's really a storefront like any other these days. A detached response of being a responsible consumer is the only effective way to approach this IMHO.
timppu: At least by buying shares you are buying actual clout to company's business decisions, and most importantly: you are putting your money where your mouth is. Then it is also your money at stake when you tell GOG how they should be running their business.
Expecting the average store customer to buy shares is far fetched, no offense... but you can influence things as a consumer, since it is in their interest to get you to spend more money here, therefore they have to cater for your needs in the end or risk going out of business.
