[DuncanWaring]

“[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.”

Every bomb dropped with the goal of slowing Auschwitz would be a bomb diverted from winning the war.

Also, it was not just a matter of "OK, today we'll bomb Auschwitz, tomorrow we'll get back to bombing refineries, or factories, or whatever". It was not unheard-of to lose 20% of the attacking bombers in a single mission.

[SJackson]

Every bomb dropped with the goal of slowing Auschwitz would be a bomb diverted from winning the war.

I don't think it would have been particularly effective. The author presents a brief quote from Madoff who I believe has suggested it would have been a legitimate secondary target. If the primary, in Auschwitz's case I believe tire factories a few miles away, were clouded in, bombing the camps might have been better than dumping bombs into the sea. I can't disagree with that. But neither the author nor I believe Madoff has suggested they should have been primary targets. Some have, and interestingly they usually don't blame FDR. Rather the US for the decision.

[rmlew]

Every bomb dropped with the goal of slowing Auschwitz would be a bomb diverted from winning the war.

You seem to be under the misconception that the only facility at Auschwitz was Auschwitz II aka Auschwitz-Birkenau. There were actually over 20 facilties, most of which were labor camps (ie work to death), which produced synthetic rubber, chemicals, and other goods necessary for the German War machine.
As far as I am concerned, members of the US military protected German production lest any Jews be accidentally saved.