The Dark Knight didn't deserve any nominations in my opinion, no matter how popular it was. Ledger's performance was excellent, but it was not a challenging role. Downey's performance was much superior, much more challenging technically and even funnier.
Sites like metacritic or Rotten Tomatoes can still suffer sampling errors. The large number of samples doesn't remove the problem of rating ambiguous reviews. Even worse, regarding critical reviews as samples of a move's quality, then simply counting them doesn't address systematic errors in the reviewing process. Such as the desire of critics to not be too different from their audience. Indeed, many critics operate as a feature designed to attract readers, and their reviews as a whole operate as barometers of popularity, not artistic quality. The emphasis on internet feedback has sharpened this tendency.
Don't forget, reverse snobbery ("just plain folks" or faux populism) is no more valid than snobbery.
Anyone who imagines Hollywood is some far left ivory tower either hasn't actually been paying attention to what's on their screens, or has a far right perspective. Or both.
As for rants about PC---everyone who is being honest knows that pretty much the only "PC" that is widespread is disdain for people who use racial epithets. Feeling that is dire insult says too much about you.