JEWISH answer: Islam is NOT an ethnicity. One can be a Christian, Druze, Jew or atheist and be of Middle Eastern ethnicity.
Judaism is NOT a race! Nor an ethnicity.
What would you call a non-observant Jew? A non-observant, lapsed or secular Jew. What do you call a Jew that converts to another religion? An apostate that is no longer part of the Jewish community nor part of the religion
You can change your religion and no longer be considered Jewish.
You cannot change your ethnic background.
Here's an experiment: look up photos of Yaphet Kotto, Alyson Hannigan, , Adam Sandler, Natalie Portman, Lauren Bacall and Harrison Ford
Are Jews one ethnic group? Obviously not - all of them were born Jewish.
Being born Jewish refers to Jewish law – there are responsibilities and privileges in Judaism and laws were established to determine who is a Jew and who isn’t. That does NOT mean being Jewish is a race or ethnicity.
For example: one cannot partake of communion in a Catholic church unless you are Catholic and have recently gone to confession. A non-Jew cannot read from the Torah scrolls at synagogue.
Added: actually that's a lack of common sense. Not all Jews are Israelis and there is no such thing as an Israelite, that's an archaic (no longer used) term. Not all Israelis are Jews either.
Jews are Jews - how hard is that?