Because they aren’t comparable and don’t belong in the same sentence honestly. The name is the same, genitals are getting mutilated, but one usually means a lifetime of pain and discomfort while the other usually means some loss of sensitivity.

Female circumcision is done explicitly so that the girl will never experience sexual pleasure. No anesthesia, sometimes they rub animal shit in, sometimes they sew the vagina close to get forced open on the wedding night.

Male circumcision is usually done in a hospital, and usually the intent is more something like thinking it prevents phimosis - which it might actually even be medically necessary in that case. It’s not done in a way to deliberately destroy function.