This is an emotive subject but in this case I think that the Allies were right - the main goal was to end the war and eradicate Nazism in order to prevent these things happening. I honestly do not believe that anti-semitism was a factor.

On a practical level, Auschwitz would have been a 'deep-penetration' raid and would have had to overfly the whole of Germany, or go via the Baltic and then a long way down into Poland leaving the bomber stream vulnerable to night-fighter attack. 'One-off' raids could be costly and only partially successful ( eg Peenemunde , Mailly-le-Camp ).

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