Art is subjective. When I do Hugo and Nebula nominations and voting, I nominate and vote for what I *like*.
So does everyone else. The theory is that if you get enough people voting then the good stuff will rise to the top, but…so.
Last year for the Lodestar, I almost had to roll a dice to choose between the nominated books. They were all that good. At that point, you start choosing based off of things like the specific tropes the writer employed, the precise sub sub sub genre.
And, yes, the demographics of the writers are GOING to come into play.
Another factor that comes into play is awareness.
And how much somebody wants the award — writers and publishers who are willing to provide copies of their book to voters have a huge advantage over those who aren’t. (And I’ve set aside a nominated book before because the digital copy they provided was broken. Is that fair? No, but it’s reality. It’s not the writer’s fault their publisher couldn’t find anyone to make a working epub for them, but it’s GOING to affect their chances).
This means that sometimes the best book of the year isn’t going to win. That’s just the way it is.