Outside of the very real issue of transmitting a culture, like many “enlightened” people, I have to overcome a gut reaction against the idea of cutting a baby. Since I’ve yet to find that our shared spiritual path is inherently inconsistent, however, I’ve tried to develop with some ideas which I think fall much more strongly into explanations than apologetics.
The extended Shabbat P’sukei D’zimra includes the phrase, “sur mey-ra v’osey tov”, turn away (or remove) evil and do good. In the past I’ve relied on the thoughts of the “Meor Eynayim” (founder of the Twersky dynasty) who talks about the need for a teacher to insist on growing levels of tshuva from his/her student before revealing/discussing ever-deeper levels of meaning.
A Brit Mila, however, is, obviously, much more physical and I think the significance is also much more obvious and physical. It’s not mere chance that the penis has a portion which is expendable. And it isn’t radical feminism or male self-hatred to observe that most tikkunim of humanity at this point in our evolution have to do with blunting aggressiveness and raising the feminine and balancing it with the masculine.
The circumcision itself only begins the process of completing and perfecting a man by de-emphasizing all that the penis has come to symbolize. Just like birth is only the beginning and that pain will also soon fade in memory (so I’m told, of course). Now that we’ve done the “sur mey-ra”, removed the excess emphasis nature gave men, we now have to “osey tov”. Perhaps it’s fortuitous that we’re approaching Purim where, not even that far beneath the surface of the story, the real action is the elevation of the Queen. And as I’m sure you’ve studying in many approaches to kabbalistic symbolism, the important tikkunim, no surprise, are the opening up and the elevation of the feminine, bringing it to balance with the masculine in the ultimate “yichud”. Yehi Ratzon that the seeming cruelty and pain is actually Chesed which helps him begin this process by removing such a basic and obvious obstacle.