2. It is a Quranic command to follow the “Creed of Ibrahim.” Those who do circumcision considering it to be part of the creed of Ibrahim, I can understand as to why they are doing so.
The practices that are attributed to the creed of Abraham are relying on what our ancestors have given us. The Quran states that we should judge what they have told us using the Quran. This is now the criterion to judge whether their practices were authorised by Allah and hence whether we should continue with them. The Quran cannot tell us everything they did and yes or no to follow it, so it GIVES US THE GENERAL RULE THAT IF IT IS AUTHORISED BY QURAN, DO IT, IF NOT, THEN REJECT IT, or do not make it a religious obligation.
You may not have mentioned circumcision but your beliefs include ancestral worship and this includes circumcision
2:213 Mankind were one single community (but selfishness divided them). So, God sent Prophets as bearers of good news and warnings. He sent down with them the Scripture in absolute truth that it might judge between people wherein they differed. But again, out of mutual rivalry, they divided themselves after all evidence of the Right had come to them! So, God shows the lighted road to those who would acknowledge the truth and thus resolve their disputes. And God guides to the straight road him who wills to be guided. [Satan, the selfish desires, had rent asunder the unity of mankind. 2:36, 10:19. Using the perceptual and conceptual faculties in all humility help people achieve guidance, while selfishness, arrogance and blind following lead them astray. 2:170, 4:88, 6:56, 7:173, 7:179, 17:36, 27:80-81, 30:22, 37:113, 40:34-35, 41:17, 56:79]
3:23 Have you noted those who were given a share of the Scripture? When they are invited to the Book of God to judge among them, a party of them turns away in displeasure.
4:105 We have revealed the Book to you in absolute truth that you might judge between people according to what God has shown you (in this revelation). So, do not be an advocate for the treacherous.
Many more verses which say follow the Quran , not ancestor.