Earlier quoted context omitted.
>the religious POV There is no "the religious POV" and for some purposes, it seems practically and morally compelling to use a similar definition to what persecutors of Jews use, rather than a traditional religious one.
Jews don't define themselves based on how antisemites defined them.
According to the Wikipedia article on Israel's Law of Return, in 1970, it was extended to people with one Jewish grandparent or married to a Jew.
"There are several explanations for the decision to be so inclusive. One is that as the Nuremberg Laws did not use a halakhic definition in its definition of "Who is a Jew", the Law of Return definition for citizenship eligibility is not halakhic either. Another explanation is the 1968 wave of immigration from Poland, following an antisemitic campaign by the government. These immigrants were very assimilated and had many non-Jewish family members."