According to the standards of the American Reform movement since the mid 80s, you count as a Jew in a Reform context. Outside of that context you might be welcomed but wouldn’t count for a minyan.
We are a nation called Am Israel in Hebrew. Doesnt matter if a Jew looks white, Ethiopian, Indian, Persian, North African or whatever. We are one people with a common heritage. What gets called the cultural aspect in the US is basically from Europe but thats far from the default setting worldwide. What in English is called Judaism is simply the contract between our people and God. Thats the foundation of any Jewish culture anywhere.
BTW side note, we had almost 300 people at the Chabad Seder in Tokyo! Jews from all over the world celebrating our freedom and it was AWESOME!
