Because it's the opposite of net neutrality. It's picking winners and losers. If Facebook is free, but you have to pay for local home grown Indian social networking sites, well then how will those businesses ever compete?

Personally, I'm torn. I'm all for free access to Wikipedia. The problem is, not all of the world's knowledge exists there, so you therefor are only giving people a taste of knowledge.

With Facebook and Google, you are choosing the silos for people, and making it very very difficult for competitors. And without competition, localized monopolies tend to stagnate, which ultimately hurts consumers.