In his  book, “FDR and the Holocaust: A Breach of Faith.” historian Rafael Medoff says Franklin Delano Roosevelt failed to take relatively simple measures that would have saved significant numbers of Jews during the Holocaust, because his vision for America only encompassed having a small number of Jews.
“In his private, unguarded moments, FDR repeatedly made unfriendly remarks about Jews, especially his belief that Jews were overrepresented in many professions and exercised too much influence and control on society. This prejudice helped shape his overall vision of what America should look like — and it was a vision with room for only a small number of Jews who, he said, should be ‘spread out thin.’ This helps explain why his administration went out of its way discourage and disqualify would-be immigrants, instead of just quietly allowing the immigration quotas to be filled to their legal limit.”
 It really goes beyond that. FDR did not want to publicly speak out against the impending genocide
On August 25, First Lady Eleanor Roosevelt brought her friend Alice Hamilton, who had recently spent three months in Germany, to Hyde Park to give FDR a detailed eyewitness account of German brutality against the Jews. He still refused to publicly criticize Hitler.
 There were many actions FDR could have taken to stop or slow down  the Holocaust
Medoff, who currently serves as director of The David Wyman Institute for Holocaust Studies, says that there were actions Roosevelt could have easily taken that would have saved well over 100,000 Jews from Hitler’s extermination camps.

“He could have quietly permitted the immigration quotas to be filled to their legal limit — that alone would have saved 190,000 lives,” Medoff said.

“He could have pressed the British to open Palestine’s doors to Jewish refugees. He could have authorized the use of empty troop-supply ships to bring refugees to stay in the U.S. temporarily, until the end of the war. He could have permitted refugees to stay as tourists in a U.S. territory, such as the Virgin Islands, until it was safe for them to return to Europe. He could have authorized the bombing of Auschwitz or the railway lines leading to it, which would have interrupted the mass-murder process.”

Asked to respond to the argument that it was better for Roosevelt to focus on winning the war than divert resources to bomb Auschwitz, Medoff said “[b]ombing Auschwitz would not have required any diversion of resources, because U.S. planes were already bombing targets that were less than five miles from the gas chambers, during the summer and autumn of 1944.”
Perhaps it wasn't all FDR's fault, Historian Benzion Netanyahu (Bibi's Father) said the American Jewish community's reverence for FDR prevented Jewish leaders from confronting the president.