I have issues with the nature of the bomb, but I think it's just too big, and the alternatives too uncertain, to judge.
I do find it odd that in the light of how our side won the war, that some people still have such a problem with German bombings of Britain. Not only the blitz suffered by London, but of other coties in the country. I'm not suggesting they should be happy, but it's not like it's anything we didn't do.