"An Unforgivable Insult to Our National Honor"
Arun has been writing about an incident in which some Indian diplomatic official was arrested and strip searched as part of an investigation of alleged human trafficking. I haven't bothered to learn the details of the case, mainly because I'm pretty sure that it would turn out to be some combination of a couple of very familiar themes: cops behaving badly and/or diplomats behaving badly. Whether or no, it seems to have become a cause celebre in India, where it is perceived as either a deliberate insult to their national honor, or, perhaps worse, an abuse out of negligent contempt.
I tend to go with more of an "American Hustle" type of theory - overzealous police with big game in sight and an itchy trigger finger. For my purposes here, neither the details nor even the facts really matter, however. Once a real or perceived slight has occurred, it can become an excuse to rally the citizenry for war or maybe just somebody or other's political campaign. Once upon a time, I expect great powers used such stuff to lure their citizens into actions very likely to get them killed. Great powers today have other methods, but lesser powers still find that sort of thing useful.
The US, for example, is pretty used to being called all sorts of names by both our enemies and many of our supposed friends. We don't like it, but we are also pretty used our diplomats being murdered as well as insulted. We try to punish the culprits.
Smaller powers may have fewer options, especially when the insult comes from a great power. War would be suicidal, so outrage is a default policy. It might get the great power to pay attention and it might help get out the vote.