see maharsha. doesn't one who is nolad mahul require hatafas dam bris? so there is a simple answer.
dmartin, raanana eretz yisroel
The Maharsha is addressing the question according to the other opinion that holds that one who is Nolah Mahul does not require Hatafah. (Whether a Nolah Mahul needs Hatafah or not is the subject of a Machlokes; see Shabbos 135a and Insights there.)
Y. Shaw