With reference to your comments on male circumcision: At the age of 10, I was having trouble pissing; I could only dribble which was embarrassing at the school urinal. I told my Dad, who took me to our GP. The doctor decided that I would have better flow if I was circumcised.
So onto the doctor's operating table, a local anesthetic injected, a few snips, a few sutures and I became a 'new man'. It took a few weeks to heal; the sutures dissolved and my flow was way better. A little painful during the recovery phase especially if I started to become aroused as I was already having erections and masturbating for a year or so. (no ejaculate at the stage but it felt fantastic!!)
The doctor wanted to perform the procedure right away as he wanted to beat my erection onset (or so he thought). I was flaccid during the operation - no sensation due to the anesthetic, but I later realized that this is the best state to be in.
Your comments I think apply to the circumcision of baby boys, which was done, even in first world countries, with no anesthetic, straight after birth - a most cruel custom. I know that boys are cut in many parts of the world at older ages with no pain relief and in unsterile environments. I wasn't aware that there was a requirement for the penis to be erect. If I can bring myself to watch some videos of the procedure (without grabbing my appendage as we all do in sheer fear) I'll look for this.
I'm not sure of the reason men have a foreskin. I lost no sensation with it's removal, in fact, I'm way too sensitive and suffer from premature ejaculation especially if I'm a bit pent up and it's been a while. After I cum (usually two or three times within a couple minutes), I seem to lose my libido and cant be bothered to carry on as the bullshit porn industry tries to suggest is possible.
Regarding sexual sensitivity, who would agree with me that ticklish people are way more sexually sensitive and climax very quickly; women included? An old friend (way older than me) once told me to marry a ticklish woman (as apparently his wife was). I have always been very ticklish!
So, my being cut gave me way better flow in urination, and made hygiene better. It didn't cause me any impediment to sensitivity - in fact, I wish I could find an ointment which would desensitize me !!
I never had any complaint about abrasiveness in vaginas (or elsewhere), my glans etc are very smooth and non irritating.
I agree with the general sentiment of your post. I thought people might be interested in my experience. There are medical reasons for circumcision to be done (as there are for most medical procedures). Phimosis is one common reason for boys and men to be circumcised.