Who could say something so horrid? You?
Anyone who uses the logic you and others like you utilize: defining personhood based on the arbitrary properties of a human zygote rather than inherent properties such as consciousness, self-awareness, ability to form thoughts, dreams, and relationships/bonds with others, etc.
The logic your side utilizes is already in place by defining certain zygotes (those with human DNA) as persons and other zygotes (those with chimpanzee DNA, for example) as non-persons. What's stopping someone from saying that those zygotes with Jewish DNA are non-human and not persons using your line of logic? Saying that such a statement is horrid is not a counterpoint. It follows directly from the arbitrary nature in how your side defines a person.
Instead, if we define personhood based on properties using reason and logic and delve into the deeper reasons why killing a person is wrong, then there is no logical or rational basis to define a Jew as a non-person, since as long as a Jew has the properties that make a person a person (such as consciousness, etc., the properties I defined previously), then there is no dispute, and someone who says they are not a person is objectively wrong since it is an objective fact that both Jews and non-Jews have those same properties that give them inherent value.