I always make sure to not use the GoG downloader just download the game. I don't need a client with your branding all over it, that has socials and my library and all engagement bait like that. I figure it's one step away from putting the DRM back on so you have to use the launcher to get a game from GOG. Just let me buy games and then shut up.
Game launchers are a good idea that lots of people want. A good game launcher needs both deep game integration and an online account, to provide save game syncing, joining friends and updating games. So far, it's mainly Steam which has been able to do this on PC. If GoG wants to compete, which it does, it only makes sense for it to provide the same.
It's not some evil scheme.