I feel like the translator's note is a bit unfair because Oshio's situation is Oshio's situation, not someone else's situation. His target of interest was Salt-God, not any normal human. At the best of times, it was difficult to figure out what she really meant, so why exactly was this time different? Oshio accepted surprisingly easily the rejection, which was actually hanging up. Yet back school, he was trying to interpret in a positive manner Satou's blunt answers. It didn't visit his mind that he wasn't even rejected, it was Satou being the usual Salt-God Satou. If you are trying to date someone with Terminator level of understanding of social interactions, grow a thick skin.
So, sure, you can say that be a man and don't dwell on it, and especially don't accept stupid morsels afterwards. But that hasn't actually got anything to do with Oshio's situation.