In American English, “race and religion” is an old-timey expression that’s typically used as a broad identifier in a melting-pot context, eg. “We are a nation of many nationalities, many races, many religions…” ~FDR

I suspect the comment means culture, which is frequently confused with race. But culture is also not uniform and will differ by individual etc.

Then maybe my other point applies. Secularism can exist within many cultures