Why is anyone Jewish?
What is it that unifies them so monolithically?
Most are not overtly religious - at least in terms of Judaism.
I believe it is based on their 'chosen people' arrogance and their stubborn resistance to Christ Jesus - which are patently inconsistent positions.
Since preincarnate Jesus is the One who 'chose' Abraham to be His progenitor, those descendants of Abraham who reject the One who 'chose' him cannot possibly be 'chosen'.
The fact is Abraham was chosen to provide the seed by which Christ Jesus would be born.
Once Christ was born of Mary of the seed of Abraham, the job was finished for which the line of Abraham through Isaac through Judah was chosen.