When boys are babies the foreskin is still attached to the glans, the two form one organ. Over time the foreskin loosens and separates and this is generally complete by the time boys hit puberty. (we've all seen how much little boys fiddle with their winkies!!)
When a baby boy is circumcised, the foreskin has to be forcibly separated from the glans, leaving a large, extremely sensitive, raw area as well as the actual cut edges of the foreskin. This separation is done by pushing an instrument between the fused foreskin and glans and ripping the skin away. After this has been done, and it takes a lot longer than a "couple of seconds" this raw area is exposed to urine every time the baby wee's, and even if it is dressed will rub against the nappy etc. This causes pain for several days until it starts to heal. Infections are not uncommon, after all, clinically speaking, this is a "dirty" area.
Older boys and men are given full GA's for circumcision, and are left with much less "raw" areas as their foreskins have at least partially separated, depending on how old they are when the operation is performed. Babies are not required to be given any real pain relief until they are at least 8 weeks old, and local anesthesia is not terribly effective as it only numbs the very surface of the skin, and not all of the layers that are cut during circumcision.
From what I can find out, I believe that originally ritual infant circumcision involved pulling the "excess" skin forwards and snipping it off, not ripping it back away from the glans as is done now. The same is true for ritual circumcision of older boys, there is no forcible separation from the glans, just removal of "loose" skin, which does still cause pain, and carry infection risks, but is not as physically traumatic as infant circumcision.
The modern trend in the US for circumcision was started by Mr Kellogg (he who brought us Corn Flakes) and his motive was to reduce and discourage masturbation by reducing sensitivity. Incidentally, circumcision can also significantly reduce the potential length of the erect penis too, so these babies turn into men with shorter less sensitive penis's.
The idea that it is hygienic is laughable, it doesn't take a rocket scientist to keep a willy clean, and the argument that it reduces infection (in normal penis's, not those which actually do have overly tight foreskins) is crap too, the UK and Europe is not populated by men with fetid rotting knobs and rampant urine infections, and yet most British/European men are not circumcised. How can this be?????
It doesn't matter how you shake it, performing surgery on an un-anesthetized patient is ethically wrong, and having your defenseless baby mutilated in the name of religion is morally abhorrent.