Oscars don't mean anything in terms of acting skills. They are and always have been more about politics than anything. He doesn't align himself with how Hollywood wants people to be. His movies are too good to be able to pass up on nominations but they won't give the oscar to someone they don't like. Same with Bradley Cooper.
The Revenant is based on a cool badass American that was real life. Of course Hollywood exaggerates it. His name was Hugh Glass. I'm not sure why they released the movie on Christmas day but I'm a fan of the western dramas so I'm going to see it, but I don't like every movie he has been in