From the article (boldface added):
Jews passionately supported and continue to admire FDR, who denied entry for Jews seeking asylum from Nazi extermination just before World War II. The most telling is the tragedy of the German ocean liner MS St. Louis, whose captain, Gustav Schroder, tried to save 937 German Jewish refugees after they were denied entry to Cuba, by bringing his ship to Miami only to learn that the U.S. refused his Jewish passengers a safe harbor. Finally the Jews were accepted by various European countries and eventually ended up in Auschwitz and Sóbibor, where half of them perished. By refusing to allow Jews to enter the United States Roosevelt offered Hitler a propaganda coup: justification of the persecution of Jews. The Nazis could say that they were not alone in their hatred of Jews; the rest of the world, and especially the United States, did not want them either. Nevertheless, Jews voted for FDR and still love him—after all, the New Deal was a giant step toward socialism.
Yes, I read that paragraph. But Roosevelt didn’t allow that ship to land because the immigration quotas set by Congress for that year had already been filled.
A quick internet search tells me that that paragraph is another thing the author got wrong. The St. Louis never even attempted to enter the U.S., because the Immigration Act of 1924 barred those refugees; the ship was turned away from Cuba and Canada before being returned to Europe.
In regards to the Saint Louis and Jews in Europe and FDR, he just kept doing better among Jewish voters.
“1939 letter found, plea to FDR to save Jewish kids”
That was in 1939, as was the St. Louis, FDR won 82% of the Jewish vote in 1932, 85% in 1936, 90% in 1940, and 90% in 1944.
Catholics voted for FDR 85% in 1932, 81% in 1936, 73% in 1940, and 73% in 1944.
Protestants barely voted for him in 1932 and 1936 and voted against him in 1940 and 1944.