Publishing remarks made as part of background for a completely different topic, in such a way as to make it seem as though they were made during an actual interview on the topic quoted, is unethical, IMO. And since that's what happened, I stand by my remark.
So, you're just wrong about this. Filed under: Ethics - Human Sources: "'On background' is a kind of limited license to print what the source gives you without using the source's name."
http://journalism.nyu.edu/publishing/ethics-handbook/human-s...
And, knowing many journalists, none of them would ever print something given to them on background with the source's name attached. It is unethical.