Buyers of kosher products in the US are not necessarily Jews. To take just two examples
Millions of Muslims throughout the world follow a dietary regimen
similar to the kosher code. Since they recognize that food products
bearing a kosher symbol conform to the requirements of Halal, foods
certified as kosher have a broad appeal to Muslims. The countless
inquiries from the Islamic community attest to the attention given to
the kosher symbol on packaging of a broad variety of products.
Muslims currently constitute a sizeable chunk of the “kosher” market. Religious Jews represent a small fraction of the overall
kosher market in the United States.
While it is not regarded as ideal, Muslims are permitted to eat meat
slaughtered by people of other Abrahamic faiths, meaning religious
Jews and Christians. “I used to always buy kosher chicken before there
was a halal alternative,” said Maffei [an influential halal food blogger and author of My Halal Kitchen]. “And I still buy kosher salami
because we don’t have that as a halal product,” she said.
To give a sense of scale (in the overall food market, not just meat), The Boston Globe reports
“More than 11.2 million Americans regularly buy kosher food, 13
percent of the adult consumer population,” Fishkoff writes. “These are
people who buy the products because they are kosher, not shoppers who
pick up Heinz ketchup, Miller beer, or Cheerios because they like the
taste or the price.” But only about 1.5 million of those customers are
Jews committed to keeping kosher, she points out, which means that “at
least 86 percent of the nation’s 11.2 million kosher consumers are not
religious Jews.” Eighty-six percent!
As such buying kosher products is not a reliable sign of Jewishness, let alone of being a religious Jew.