Ethnicity can be misleading. Bloodline does not guaranty faith in God nor equate to belief in the sanctity of innocent human life.
Jacob and Esau were twins, but Esau was so powerful and skilled in hunting he felt no need for the God of his father. And it was his grandson, Amalek, who is the quintessential man with whom God warned would make war with Him from generation to generation.
Of course, the thing that really pissed off God was when Esau sold his birthright to Jacob for a bowl of lentil soup.
"And it was his grandson, Amalek, who is the quintessential man with whom God warned would make war with Him from generation to generation."
As prophesied by God while Jacob and Esau were both still what liberals might call non-viable tissue masses which happened to be "struggling together" in Rebekah's womb.