Lots of Jews were granted asylum. The ones on the St. Louis weren't -- but they weren't exactly facing death either. The US had zero reason to believe in 1939 that ANY Jews on board were in danger.
You wrote:
“The US had zero reason to believe in 1939 that ANY Jews on board were in danger.”
Kristallnacht ring a bell? Yes, less than 100 Jews were killed, but everyone knew it hah happened - IN 1938!!!!