Barnabas is idiotic as usual. He is in tears because Sarah won't stay with him - but he completely rejects what she has to say to him. But then, he's an old-fashioned male. It doesn't matter what a female says, as long as she's decorative.
Lots of issues are framed as sexism, when there's often something broader and more fundamental going on. I think he's showing a neurotic self-induced obliviousness and denial of what he does that's wrong. He's gotten very good at tuning out and reinterpreting any messages that might make him reconsider the morality of his actions. And come to think of it, it might even take a smart man to rationalize as well as he does, and to reprogram his own thinking that well. I'm sure that if called upon, he could give an excellent, maybe even persuasive speech on why he should not have to feel guilty for anything he does.
I remember reading a paper about 25 years ago, on dismissive responses women tend to get from male doctors, and it was well-written I think, though this was a long time ago. I'd have had no reason to question the point being made, except for the fact that as a man with an unusual serious medical condition, I was receiving exactly the same attitudes, dismissals, and emotional responses from doctors, both male and female. That taught me a lesson I'll remember my entire life. There are concealed assumptions in everything we think and do.