The most obvious aspect of it is that some men are missing a rather large component of their penis. And when that part is missing, it doesn't pick up any sensations, while intact men including my husband report the part that is removed during circumcision is the most pleasurable part.

People from cultures in which women are cut claim that removing the clitoris doesn't affect female pleasure one bit. It's easy for us to see that that cannot possibly be true, but if's harder to look critically at one's own culture.