I think this is a problem about talking about two different things with the same word. When most people talk about objectification, they are talking about utilitarian principles, yes. Objectification is not actually the issue. But they are calling the issue objectification because is sounds right.
Objectification is not actually the issue. What non-rationalists call objectification is.
Rationality can often allow us to overcome otherwise debilitating emotional responses. I think a non-rationalist in the same situation who let their psychopathic brother die … they would probably feel a lot of guilt. A LOT of guilt. Finally, evolution isn’t always fine-tuned, especially in social contexts. Guilt simply may not be a fine-tuned enough emotion to make you feel pain directly proportional to the odds of you being suspected for a crime; it’s more likely that you feel guilt differently in different classes of situations rather than in different levels of the same scenario.