There are many types of circumcision, some are very loose which allows the male to keep more of his skin, they often resemble a male with a naturally short foreskin. There are also tight circumcisions where the scar is well below the head. As with all infant penises there is no way to know how it will change and grow as he develops. Being from the US and changing plenty of little boys diapers, all the circed boys I have seen have fully exposed heads.
Below is a link to a slide show drawing of the infant male anatomy both natural and surgically altered.
The reason I find it shocking is because it looks like an aroused man.
What I find odd is the amount of people here in the United States that do not realize that once an intact man becomes erect the foreskin retracts and looks like a circumcised male minus the scar and plus the frenular delta, ridged band and 20,000 nerve endings.- This is why I don't get the cosmetic argument. When its erect it looks pretty much the same plus the full function.
As far as the locker room argument I think your right. All penises wether flaccid or erect are different and unless you really know what your looking for and are truly looking you don't notice. My husband played football from 5th grade through high school with the same group of guys and he does not know any of their penis size or status. I feel like its similar to asking a girl what her friends nipples are like. How would I know if my friend has flat nipples?