Why will they be talking about Dresden in 100 years time?
This is the reason for bombing of German cities:
They tried to terror bomb Britain by orders of Adolf Hitler.
Bomber Command bombed Berlin first. Some say Bomber Harris did it to provoke Hitler to redirect the Luftwaffe from air fields to anything else. Others say that it was an accident and that all that was hit on that first raid on Berlin was a garden shed.
They put children in ovens
Churchill and cabinet approved the bombing of cities in Feb 1942. At the Wannsee conference (Jan 1942) only the deportation process was agreed to. How to carry out the exterminations was not settled.
My only point being that Churchill, who had once argued against the bombing of civilian targets, did not know about the ovens in Feb 1942 because they did not exist at that point in time.
Concentration camps
were around since the Berlin Olympics, the Germans wanted to keep undesirables hidden and away and so they established a process that "confined without trial...[To]...A concentration camp, a place where people were detained or confined without trial. Prisoners were kept in extremely harsh conditions and without any rights." Concentration camps were not a secret, but I do not think that Churchill really cared about them at the time.
The Americans did not agree to the bombing of civilian targets until 1944 (Berlin), and even then people like Gen Doolittle tried to challenge the order. (Up until then they would only go after military targets, and yes, if they were in cities, then and only then would they bomb the city.)
Allied command knew about the extermination camps in 1944, but even after repeated pleas, they chose to not target them. The Allies could have put a stop to the efficiency of the Nazi extermination process and saved 100,000s of lives.