https://www.kitguru.net/gaming/matthew-wilson/gog-speaks-out-against-review-bombing-as-hitman-gains-criticism-for-online-requirements/
 
GOG is best known for delivering DRM-free PC games, and while Hitman (2016) can be played offline and without any form of activation, many in-game features are locked off without an internet connection. Aside from certain missions, features like unlocking new equipment, unlocking new in-level starting locations and even mission scores do require an online connection. As Eurogamer reports, this led to a very low 1.4/5 user review score for the game on GOG.
 
GOG stepped in to address the complaints in a forum post, stating that the team is looking into the issues and will have an update “in the coming weeks”. However, the team also pointed out that it has a ‘no tolerance’ policy when it comes to review bombing and as a result, posts that do not meet GOG’s review guidelines will be removed. This of course kicked up some additional backlash, as many reviews were describing issues with playing the game in offline mode, as many GOG users tend to do. The argument could be made that if so many features are locked behind an online connection, should it be sold as a ‘DRM-free’ game on GOG at all?
 
GOG has yet to address the issue again publicly, but we’ll be keeping an eye out for further updates.
 
I personally think the complainers should wait for the update. 

If IO Interactive was not ready to release '16 Hitman DRM free, then they and GOG should have not agreed to placing it on a known DRM free store.