Are they actually good gamers? Not trying to bring down Overwatch, but from my experience, journalists absolutely suck at MP games.
It's not too surprising to see OW win because it's incredibly well designed to be casual, so it's a total breeze and joy for near anyone to play.
I've seen people play COD, BF, Titanfall, and nearly every journalist who plays it is god awful trash and dont know what they are doing. It's the nature of MP games where you dont have time to play at your own pace.
Overwatch is different in that there are very easy characters to play, everybody is rewarded with their special buildup, and maps/modes are straightforward. Sure, there is skill and strategy that develops from that, but the pick up and play experience is completely unlike any other MP game
Again, not trying to say that's a knock on the game, but that's what makes it so fun and easy to pick as GOTY. More people can simply enjoy it without putting in more effort needed in other MP Games.
Personally, I wanted Witness to win. I think there is more to say about that game's design, but at least it got a nomination.