MarkoH01: Nope, GOG does not even HAVE age gates at all. All they have is a security message which can simply be clicked away. Also, as with the other game there does not exist any rating at all for the PC version yet, so it is up to GOG to decide which rating they would want to chose as they are responsible for the content they provide. If you should worry about what the publiashers might think about GOGs rating: I have been told by GOG that publishers always verify the game pages before the final release so apparently they are fine with GOGs rating.
Anyway: if there would be any true age gating on GOG the rating might have been problematic for sales but since the "gating" only exists in form of a security message the whole discussion - once again - imo is completely pointless and unnecessary.
Just my 2cts and the only thing I will say to this.
Technically it's an age gate but it doesn't matter what you call it.
Apparently they still sell these to german users so it doesn't actually seem GOG is worried about that. (and they really shouldn't be)
Now that is very interesting. Idea factory is fine with
https://www.gog.com/en/game/death_end_request_early_bird_special then?
Perhaps they look at just the page, and not the age gate/warning leading to the page?