I think we can take a quote from the man himself to understand why it is not a 'controversial topic':
"The Germans entered this war under the rather childish delusion that they were going to bomb everyone else, and nobody was going to bomb them. At Rotterdam, London, Warsaw, and half a hundred other places, they put their rather naive theory into operation. They sowed the wind, and now they are going to reap the whirlwind."
- Arthur 'Bomber' Harris