Oliver Kamm, on Arundhati Roy, first here and then some more here.

.... "having entrusted her historical appreciation to Chomsky she can come
up with dogmatic assertions such as: "The bombing of Hiroshima and Nagasaki was
a cold, calculated experiment carried out to demonstrate America's power. At the
time, President Truman described it as 'the greatest thing in history'." The
origin of Ms Roy's statement is probably Chomsky's own assertion 40 years ago in
a debate in the New York Review of Books that "the bombing of Nagasaki, in particular, was history's most abominable experiment", but at least Chomsky appears to have become warier of this claim. In his 1996 book of interviews (one of so very many books of this type) Class Warfare, he states (emphasis added): "My impression is that the Nagasaki bomb was basically an experiment.... Somebody ought to check this out, I'm not certain."

..."Truman did, by the way, say to the officer who handed him news of the
Hiroshima bombing: "Captain Graham, this is the greatest thing in history." It
doesn't appear to have occurred to Arundhati Roy that "greatest thing" in this
context might have meant "most awesome event" rather than "that's simply
wonderful news".