I don't think people are complaining about Larson not smiling and thus her not being "pretty enough". People are complaining about her coming across in the trailer as having a total personality vacuum. It isn't helped by the fact that the few lines she has, she speaks in an uninterested little girl voice. It's not some sort of sexist attack on Larson not being feminine enough, it's about expecting the new big MCU superhero to be larger than life, to create awe, and have the charisma and screen presence that the character deserves. I'm not surprised the professionally offended are labelling fan criticism as a misogynist/sexist attack in order to dismiss it, that's what happens nowadays. The fact is that the fans don't care about the character's gender (they've been buying into Captain Marvel as a woman for years), they just want the movie to be stunningly good and blow everyone away.