Did Arabs before Islam seek emasculation?

It has not been established that Arabs in the pre-Islamic era (Jahiliyyah) sought castration. Castration is absolutely forbidden in Islam for humans, and for animals if there is no benefit or دفع ضرر (warding off harm) in it.

Castration of humans is Haram (forbidden) by consensus. As for the castration of horses, there is a difference of opinion. Castration of other animals is permissible if there is a benefit in it; otherwise, it is Haram.