I realize sexism is very insidious, so I understand your interpretation, but I think that's an overly cynical view that you have there. I'm a man, so maybe what I think on the topic doesn't hold much weight, but, for what it's worth, neither my wife nor my (female) coworker thought the movie was sexist. Valerian might have saved Laureline - twice if you count when they were trapped in that weird sticky body bag thingy earlier on - but Laureline also saved Valerian's life twice. I don't see why it matters that she was made to wear a fancy (not sexy) dress and didn't fight in this particular sequence, especially since we saw her fight elsewhere in the movie. Laureline is depicted as a very strong woman throughout the entire film. Valerian is the only one with the sexist view that he should be the one to fight and protect her, and learning not to be a sexist douche is basically his entire arc.
I don't see how the script is out of touch, and Luc Besson's career-long track record with strong female leads puts most directors to shame. Laureline is no different, even if she dared touch a butterfly, was forced to wear a dress in one scene, and was saved by Valerian the same number of times she saved him. Besides, I don't see how you can call what she does in the film "swooning". She consistently calls him out on his sexism and only accepts being in some sort of relationship with him once he has shown that he respects her as a person and put his trust in her. Obviously, they've been partners for a very long time. He may act condescendingly, but there's still a lot that's good about him and she would know it better than anyone, and he has grown by the end of the film, so I don't see what's wrong with her loving him.
