Until last weekend, Pope Francis earned nothing but praise from the American Jewish Committee. But when the pope, speaking off the cuff, likened European migrant and refugee holding centers to concentration camps, the advocacy group’s response was swift and sharp.

“The conditions in which migrants are currently living in some European countries may well be difficult and deserve still greater international attention, but concentration camps they certainly are not,” said David Harris, the committee’s chief executive. “The Nazis and their allies erected and used concentration camps for slave labor and the extermination of millions of people during World War II. There is no comparison to the magnitude of that tragedy.”

As a Jewish convert to Catholicism, I sympathize with the committee’s desire to guard against comparisons that would risk minimizing the Nazis’ appalling crimes. Even so, it seems to me that Mr. Harris, in urging the pope to use “precision of language,” could use some precision himself.

Calling the living conditions at sites such as Moria, the place on the Greek island of Lesbos that Francis called a “concentration camp,” merely “difficult” diminishes the gravely inhumane treatment that men, women and children are suffering for no other crime than wanting freedom and a better life. It fails to acknowledge the hopelessness at places like Australia’s island prisons for migrants where, as Roger Cohen wrote in The New York Times, “human beings have been left to fester, crack up and die.”