I have not been able to find much evidence that permits the tracing of this usage. My recollection, though, is that it came into vogue in a bureaucratic context in universities--in my case at Hunter College. According to President Jacqueline Wexler, the student occupation of the campus some thirty years ago was "inappropriate."
The appeal of the adjective as a replacement for "bad" is that it appears to be objective. The usage also seems to accord with a popular version of situation ethics, where something that would be acceptable in one context is deemed not to be so in others.
Thus wearing dirty jeans or using four-letter words at a job interview would not be the appropriate thing to do. On a beer bust, though, they might be.
By this standard when is it ever appropriate to pepper spray peaceful protesters? Perhaps it is with nonpeaceful ones, though that is by no means clear.
One can also imagine insidious variations. Thus the Rev. Paul Shanley's serial acts of pedophilia were "inappropriate." Bush's invasion of Iraq was "inappropriate." Qaddafi's conduct during his regime was "inappropriate." And so forth.
Labels: English usage