A PSA on Jewishness, because apparently non-Jews just have to know this stuff and can't figure it out on their own

Jews are an ethnic group. Global Jewry is made up of several different ethnic groups, the largest of which are: Sefardi Jews, whose ancestors historically lived in the Iberian peninsula (Spain and Portugal) and western Europe; Ashkenazi Jews, whose ancestors historically lived in central and eastern Europe; and Mizrahi Jews, whose ancestors historically lived in MENA (Middle East/North Africa). There are other groups of ethnic Jews living in other places in the world as well. Jews from all of these groups have moved across the world, largely due to persecution in their host countries, and formed new communities in new places, so that there may be longstanding communities of Ashkenazi Jews in France, and Sefardi Jews in Morocco.

All ethnic Jews have ancestral, genetic heritage stemming from the Levant (specifically, the area now known as Israel and/or Palestine). All Jews also have cultural heritage stemming from the Levant. This is no less important or relevant than genetic heritage.

Some Jews have mixed heritage (one Jewish parent only). They are also Jews. The matrilineal descent question is a question of Jewish religious law, and is interpreted differently by different Jewish denominations and individuals. (My personal stance is to affirm patrilineal descent.) 

The religion historically practiced by Jews is Judaism. Ethnic Jews may practice any religion they please; this does not mean they are less Jewish in terms of their heritage. Non-ethnic Jews may convert to Judaism; this does not make them any less Jewish in terms of their religious practice. Judaism does not proselytize.

Judaism as a whole takes no global stance of Zionism as a political ideology. Different Jews have different opinions on Zionisms (plural intentional, because Zionism takes a lot of forms), and while they may be good or bad people, and you may agree or disagree with their politics, their Zionism or anti-Zionism does not inherently make them any more or less Jewish. 

The question of Jewish identity is ultimately not the purview of non-Jews. It is nothing more or less than gross arrogance for non-Jews to assume that their opinions on this question are remotely relevant or of interest to Jews, and the persistent insertion of some non-Jews into these private conversation is extremely offensive.

If you are not Jewish, and have written, or are considering writing, a post on  Jewish identity/ethnicity, I have some advice for you: don’t. You almost certainly don’t know what you’re talking about, and you definitely can’t have a better understanding of these complex issues than someone who is actually Jewish themselves. If you really feel, for some inexplicable reason, that you simply must weigh in on this issue, consult an actual Jew before doing so.