If Hashem wanted us to be circumcised why didn't he create us that way? If the world could not endure without Bris Milah, why did Hashem first command this Mitzvah to Avrohom Avinu and not Adam or even Noach? How could Hashem tell Avrohom he was defective (a ba'al mum) without a Bris if that is how all mankind appeared?
Why did Avrohom make a grand feast in honor of Yitzchok's bris and not Yishmael? Wasn't Yishmael's voluntary Bris Milah at 13 years old truly a greater commitment to Hashem than Yitzchok's involuntary Bris at only 8 days old? What correlation is there between Yishmale's Bris and Hahsem's rewarding his descendants with the proprietary rights to Eretz Yisroel when Bnei Yisroel are in galus (exile)?