In the still-early days of internet at least 3 companies had Free Dial-Up Internet service suplimented with ads. They gave you access to ALL of the internet and simply put an ad banner on the bottom of the screen at all times you were connected. We had Net-Zero (FREE dialup internet with Ads), K-mart Blue-Light (FREE dialup with ads), and Juno (FREE dial up with ads). All three of them went off of the FREE ad based model eventually because it was unsustainable (downloads and Napster required larger and larger amounts of bandwidth). This wouldn't work today due to ad blockers and torrents. Internet.org doesn't even give you access to the whole internet. So the only way for this to pay off is for Facebook and Co to become a monopoly in India.
You might not care because it's an American company expanding its influence abroad, but how would you feel if China did the same to us in the USA? And we had no chance of ever developing Facebook?