Amazing that GOG was so lazy that they didn't check to ensure their DRM removal was complete, before offering it for sale. Hopefully this will motivate them to do a proper fix.
How would you check for something you don't know about? They probably tried the game and when they couldn't win they ascribed it to insufficient skill. Even if they searched for information online, they probably (like OP) found discussions where some people complained about the game being unwinnable and got "you just suck!" replies.
Honestly, it was a dumb thing to do by the original developers.