No allied bombing of Auschwitz?

[John Wilson]

Escaping jews, and sneaked-out photos (taken at great risk to the Sonderkommando who took the pics) showed the allies that such horrors were indeed occurring at these work and death camps.

Officially, SHAEF were said to have decided that the bombing of such camps (namely Auschwitz death camp) were too costly in men and materiel when stepping up for D-Day etc?

Yet only days later, a huge formation of US B-17's bombed a ballbearing factory nearby - some overdropped their target...and accidentally hit some of the huts at the camp, killing a few guards!

So, why was there no allied bombing of these camps?