Vonnegut and "Slaughterhouse-Five" have an interesting back story. I first saw the movie while in high school with our church youth group (?) I found it confusing, but the college-aged kids couldn't stop talking about it (they'd had more education, and obviously read the book first). Later, I learned about the autobiographical element (interesting, as my father was also a German POW in Stalag Luft III, the Great Escape camp). Vonnegut was briefly a Chem Major at Cornell (which my father also attended), studied engineering, and later worked at the PR Dept for GE. He hung out with the early Quantum Physicists, and knew enough about their ideas to formulate his own "time is an illusion" thoughts (this being a sort of quantum possibility). I see the book now as a kind of symphony of his life experiences, and his hearty attempt to explain it all.
In any case, back to Stalag Luft III and the roughly 300,000 Allied POWs, there truly WAS no reason to bomb Dresden, and it turns out Hitler wanted to place our prisoners in German cities as "human shields" afterwards (as retaliation). Only by some interventions of other Nazi officers (who knew the war was a lost cause), prevented some further senseless slaughter. My article:
https://medium.com/p/cbba4c4f31c1
The Dresden bombing was directed by Britain's Sir Arthur Harris, who along w Monty's useless Normandy bombings, killed many innocents. Gen. Curtis LeMay is responsible for much of WW IIs other questionable bombing campaigns (he was actually busy firebombing Tokyo and klling maybe 300,000 innocent civilians at the time of Dresden, but had previously led questionable bombing campaigns in Europe). LeMay also cost the lives of many airmen (including all but two of my father's B24 crewmen) with his quetionable tactics (sending them up without fighter escorts, in bad weather, w faulty equipment). LeMay was basically Dr. Strangelove, he came out of the war a hero but cost many innocent lives. There was some "ends justify the means", but questionable nevertheless.
WW II sucked, but it did give us Vonnegut, Heller, Salinger, Mailer, and Hemingway, perhaps giving humanity a chance to take corrective measures.