I went your link, Mink, and found the text somewhat polemical.

St. Paul declared that Christians were free to become followers of Jesus without being circumcised, it's true, and he added that the same reasoning would apply to every other Jewish practice. After all, he argued, the Christ had fulfilled and replaced the Torah (which they, unlike other Jews, had come to understand as a burden). Now, consider the historical context. It had nothing to do with compassion for the suffering of any circumcision rite. For one thing, the early Church wanted to make converts, not to scare them away. More important was a theological matter. The early Church was breaking away from the Jewish community. To do that, it declared that God's covenant with Jews had been replaced by a universal covenant (that is, with all followers of Jesus no matter what their ethnic origins). By the way, Vatican II has proclaimed a very different doctrine (Nostra aetate)--one that affirms the continuing covenant between God and the Jews.

As for the evolution of circumcision, the early history is somewhat murky. Consider the story of Dinah (Jacob's daughter) and Shechem in Genesis 34 (which probably entered the canon long after the days of Jacob). In order to marry Dinah, Shechem (a Hivite, not an Israelite) promised Jacob that he and his male household will be circumcised according to the Israelite custom. But to take revenge on Shechem for having had extra-marital sexual relations with Dinah (which might or might not have been classified as rape), Jacob's sons murder Shechem and all the men of his household--all of whom are still incapacitated by pain three days after being circumcised (Gen. 34.25). So circumcision in that period was clearly very painful. That's hardly the case for circumcision among Jewish boys (at eight days old) in modern times. It probably is the case, however, among many Muslim boys (at varying ages from a few days to puberty).