People making these arguments have never been to 3rd world countries, I assume.
Privacy comes at the top of Maslow's pyramid, we are talking about basic needs here.
This has nothing to do with basic needs of the recipients and everything to do with cementing Facebook's stranglehold on social networking in the developing world. There's no "next step" from here that would make Internet.org a reasonable path on a community's technological development -- this is a dead end.
When you buy medicine it makes the pharmaceutical companies cement their stranglehold in medicine world.
Beside the above obvious point, the real point is not whether there is a benefit to providing access to Wikipedia with strings attached. The real point is this: are we giving up more than we are getting if we consent to Facebook zero rating some content and putting up walls to deny access to everything else?
My personal option is that the bargain is very bad for all parties involved.