Whether or not Jewishness is completely an ethnicity is debatable, but a very large number of Israelis (and Jews across the world in general) aren't religious a

Whether or not Jewishness is completely an ethnicity is debatable, but a very large number of Israelis (and Jews across the world in general) aren't religious at all -- they see their Jewishness as being defined by their ancestors who were practicing Jews rather than by their own beliefs.