In my mind, I do not see Bo's reaction as knee-jerk.  I think he knew exactly what he was saying and why, and felt like his words were necessary.  Everyone's responses to his words is what I imagined to be knee-jerk, including Mila's.  She hasn't said a word, but that automatic "he thinks I'm a whore" reaction is pretty knee-jerk.  If she had given herself a moment to think about it instead, she probably would have come to the conclusion that he didn't mean anything against her personally.