There's clearly a principle throughout the Mosaic law that those in leadership positions, like animals offered in sacrifice, must be unmarred. Visually, their "unblemished" appearance symbolized the requirement for those entering God's presence to be sinless. God's holiness demands such perfection -- yet, clearly, even those who were physically unmarked were still far from the sinless life required to enter God's presence.
Jesus alone lived up to this requirement. His perfection, His "being in very nature God," allowed Him to be the perfect and complete sacrifice on behalf of all of us who are marred and imperfect.
It's interesting to note that while both the Edomites and the Ammonites and Moabites refused hospitality to the Israelites traveling to the Promised Land, only the Edomites are to be welcomed as distant relations since Esau (their patriarch) and Israel were brothers. Both the Edomites and the Israelites were descendants of Abraham, and of Isaac, descendants of the Abrahamic covenant. But the Ammonites and Moabites were descendants of Lot -- not only that, but descendants of the ungodly incestuous union with his daughters after they fled Sodom. True to their roots, these people groups practiced pagan worship of Molech and Chemosh, which included child molestation, prostitution, and infant sacrifices. God's rejection of them is not a matter of their ethnicity or parentage, but of their ungodly culture. If you have any understanding of human trafficking, child pornography, and how these feed into the abortion industry, you can see that these false gods continue to have followers today, though their worshippers may not even know their names. Their ravenous hunger for the lives of innocent infants continues to demand a sacrifice which many are all too willing to make.