From what I've seen there are two types of sucessful writers, the ones that are really good at writing and the ones that are really good at understanding their audience. Stephanie Meyer gave half of teens girls their fantasy with Twilight, it didn't matter what the rest of the plot was it was going to be popular. I haven't read much about 50 shades but what I hear it's every submissive girls dream. There's not really anyone to blame, it's just the way people are. There are probably some people who can't understand why the Avengers is so popular, it's just different tastes.