It seems like it's swinging the other way with the women playing the role of the dog in the relationship. Still, a romantic comedy like Forgetting Sarah Marshall isn't vastly different than When Harry Met Sally, The Apartment or Bringing Up Baby. Conventional rom coms often imitate and deliver typical characters with formulaic plots while the really successful ones deliver individual characters and a relationship that engages and develops out of the characters.
With PASSENGERS, hearing about the twist probably did turn a lot of people off, but as far as the people who saw it, it seems like most went along with it because they were taken through the character's situation so they could see why they did what they did. Just like if someone told you CAST AWAY was about a guy who talks to his volleyball, it doesn't really cover why "Wilson" was so important to the story.
It's like saying James Bond murders a lot of people in cold blood. Taken out of the context of the film and its genre, it seems like he's the bad guy in the story.
Personally, if the roles were reversed in PASSENGERS, I wonder if there would've been the same reaction.