The Catholic Church forbids circumcision for any reason!

[VoxClamantis]

I think the passage that the OP quoted is in reference to ritual circumcision.

And "medical" circumcision is not ritual circumcision?

Circumcisions have no medical justification. See, e.g., PDF pg. 52 f. of Boyd's Circumcision Exposed.

Just because a doctor performs it doesn't necessarily make it medical and non-ritual.

Amputations are only justified if the member to be amputated immediately threatens the health of the whole body. This is not true for circumcision. Thus, if circumcisions are not medical, what are they, besides ritual? Abortions are ritual for the same reason.

My nephew had a circumcision for medical reasons - repeated infections from his skin being too tight.

Amputation of the foreskin for medical reasons that actually exist is always permissible, as is amputation of arms or legs in cases of necrosis, etc. Every situation has a context...