There are many aspects of maid-gate. Obviously she doesnt have any "right" to keep a maid while breaking local laws...in this case the law specifying what wages a maid should be paid. But the outrage seems more about:
1. The public arrest, strip search and imprisonment. Hardly standard practice for middle-class and above in India and not for Mafia chieftains, friends of Dick Cheney or senior bankers in the US either, so why was that done to her? My initial guess was that it was just standard NY Marshals douchebaggery, not India-specific. The police culture in the US being what it is (which is, in MANY ways, far superior to police culture in Pakistan or India, but that distinction may not be the first thought in the mind of an educated Indian, since our police douchebaggery is very class conscious and no diplomat would be treated like this in INdia or Pakistan unless express orders were given to the police to behave in this way)
2. Which brings us to the second cause of the outrage: the widespread belief that "this couldnt happen unless the state department wanted it to happen"..i.e. it is a deliberate insult.

I have no idea if it was deliberate or not. My guess would be "probably not"..at least not meant to be specially insulting. The State department may have felt the need to have her arrested because their quiet complaint (apparently sent in September to India) had not had any effect. Another cross-cultural misunderstanding perhaps? In this case the state department may have forgotten how fast things are processed in India?
But the dominant feeling among Indians on my timelines seems to be that "this was deliberate and meant to be insulting". Even if they are wrong, that is not a perception that will be very helpful to the US image in India.
The most interesting aspect could be what a friend from Mumbai has raised. He believes MANY diplomats from third world countries have maids (or semi-slaves) kept on lower wages in the same manner. And this may cause many of them to lose their maids. Oh the humanity!
I personally think the diplomat should have been charged once quiet messaging had not worked. But the public arrest and especially the strip search, were gratuitously insulting and unnecessary. And if they are standard part of american police culture, then that culture too needs to be looked at again...