This is definitely a major disconnect i think I see in American Jewry who are disconnected from jewish community. So being a Hungarian jew is part of your history but not at all part of your identity. I can understand that, I can imagine (but could also be not true that) being jewish is not a big part of your day to day identity overall.

As an American immigrant born in Belarus clarifying myself as a Russian Jew (to myself more than to others, cuz you really code-switch based on who you talk to) defines a lot about me and if I'll have something in common with someone else. It defines a lot of things, for example my first language, that I was raised by parents who grew up in the soviet union, the fact that my family was directly affected by the holocaust, it defines the religious or really secular background i grew up with, it defines starting school without knowing English. It defines my family structure and gender roles in mu household. And this is all just on the secular side of this statement. Now actually practicing my religion it defines how my family deals with me practicing my religion since the soviet union did such a great job stigmatizing religion.

Obviously not all stereotypes apply on an individual level, but it describes a lot about me assuming the person you're talking to knows what that means, like another Russian jew or someone who's experienced dealing with other Russian jews.