Naturally the humiliation is also due to the gay-like behaviour of the crucified on the cross. This was naturally society-dependent, me for example has no problem with males being fucked. The castration on the other hand also has in many societies no humiliating effects, think about the eunuchs on Chinese or Arabian governments (or in Game of Thrones...), but also the western cultures have eunuchs in the arts (the castrates). Naturally for me it is a horrible thought..... So there is nothing about it, however for me a horrible thought......
Castration was never sought for in itself. The violence of the flogging on a totally naked body could lead to castration when the balls of the flagrum tore the testicles.