Games get review-bombed for the silliest reasons nowadays. Often times, a fundamentalist minority of gamers feels overly protective about "their" franchise, reacting to even the tiniest disturbance with maniacal anger. If a game has a high score from critics and a low score from users, to me that's actually a good sign that the game might even try something interesting (Last of Us II would be an example here). Of course, the critics score for Diablo IV was the post-release score, not including these new patches, so it might very well be that it really is worse now...
It's worth noting that Diablo 3 went through similar pains upon release; though with less "read the room" type issues like they're having now.