Там автор пытался подстраховаться, сделав одним из условий заклятия, что оно действует только на женщин.
"Harry, the spell you used is the Sex Slave Curse and it's the parent of the modern Imperious. It's not an Unforgivable, or even illegal for only two reasons. The first is that it's ancient and requires an immense amount of power, until today, I thought there were only two people
who could have cast that spell, Tom and myself. The second reason would infuriate Ms. Granger should she ever learn of it. The curse will only work on women, and the Ministry is still mired in what can only be described as chauvinistic tendencies.