btw, yaay Net Neutraity! If you really want to help with it, go here http://netneutrality.in/ and sign the petitions and write to the government.
That being said, India really does have a net neutrality problem, so even if this may or may not be an instance of net neutrality violation, it's still something that needs fixing.
There are over 800 telcos in the world. Even if zero rating was free to the app/service provider, just negotiating with each and every telco would be a huge burden.
Zero rating is, however, neither free nor available to all app/service providers. Thus zero rating creates both a toll booth and a gatekeeper who gets to discriminate against app/service providers and pick winners and loosers.
Zero rating is a pox upon the Internet and should be killed with fire, regardless of any perceived short term benefit to some end users. In the long term zero rating is always toxic.
There are many who argue that zero rating is not a part of net neutrality and should be allowed. That's what I meant by saying that it's on both sides. I personally have mixed views, mostly leaning on the zero-rating-is-bad side, though I do feel that it may be possible to come up with a way to restrict what is allowed that helps boost accessibility of internet resources like Wikipedia without giving a competition boost.
Anyway, my point wasn't to argue for or against zero rating. I merely wanted to point out that zero rating was not objectively a part of the net neutrality debate.