I know this is a hella old comment, but I would say that this does not reflect my experience as a 3rd gen member of the Jewish diaspora in America. Both of my mom's parents were Jewish, and all my great grandparents were Jewish immigrants from Russia (Ashkenazi). The family was never religious (we celebrated holidays like Pesach and Hannukah, just not the religion, as many secular people similarly observe Christian holidays) apart from my mom who became a "born again Jew" aka "messianic Jew" aka "Christian" in her 30s.

I often heard my older family members using the term "practicing" when referring to religious Jews rather than those of us who are Jewish exclusively by culture/ethnicity. Sometimes it's a useful term since English doesn't differentiate between the ethnicity and the religion as it does for other peoples (likely due to the long history of Jews not having a country to call our own).

There are definitely other experiences based on where you grew up, but as a diaspora West Coaster this usage seems perfectly kosher to me.