For a live service game like Helldivers you could at least logically justify the account requirement but for an offline game like GoW it will just piss people.
But you could come up with a believable reason for multiplayer. (Ex. Maybe the devs decided their servers wouldn't scale and had to move to Sony's, but those require users to have a Sony account.)
For single player, there's not even a hypothetical excuse. They just want you to be inconvenienced for their own gain.