The backlash against BP getting a Best Picture nod is partly from people who don’t care much for superhero movies in general. I’m not one of those people, as I am a lifelong fan of the genre, but that’s something to keep in mind.
As for me, my problem with the movie being nominated for Best Picture is that I genuinely don’t think it was good enough to earn it. Sure, it was an enjoyable enough movie, but even as far as Marvel movies of 2018 are concerned, I preferred Infinity War. Aside from having a predominantly black cast (which, don’t get me wrong, is a big deal), there was nothing really daring or out of the ordinary about it. Sure, it discussed some serious themes and ideas, but it mostly only paid lip service to that stuff. Apart from that, it was a fairly straightforward Marvel movie with an unremarkable third act.
I’m not trying to seem like a whiny manchild or whatever, but i don’t think the Best Picture nod should go to a movie just because it has a high Rotten Tomatoes score.