Just what it says on the tin. After all, many historical societies (the Byzantines included) used eunuchs in prominent, trusted roles, and while I'm sure some of them were not entirely pleased by their involuntary surgery, the evidence weighs against the supposition that all of them hated the ruler's guts all the time (if that were the case, they would hardly have been so trusted.) If castrating infants were allowed with no opinion penalty (or a smaller one), you could, for instance, populate your council with them and have less scheming from that end.