The discussion of this (I believe in the Churchill war cabinet) ended with the decision that the best way to save the most lives was to devote all their resources to ending the war as quickly as possible.

There wasn't precision bombing in WWII. Bombing of the train tracks to the camps, or of the death chambers, would have necessarily resulted in large numbers of deaths of inmates (in the case of concentration camps), and would have been relatively easy to repair.

They mostly considered bombing Auschwitz; I don't recall active discussion of the death camps. The death camps weren't as well known because no one survived them--escaped workers from the concentration camps took the news of their existence to the Allies.