Indeed, this was the fundamental demand of al qaeda and Osama Bin Laden, for the west to halt contact with the Islamic world and stop influencing it.
- Ideological motive: Internet corrupts people, we must protect them from evil influence.
- Political motive: Disrupting infrastructure as an attack on the current rulers.
- Financial motive: Maybe they sell cable repair services or satellite-based internet access.
Or just plain vandalism, which doesn't need a discernable motive.
No way of telling without asking them, I guess.
There are people who don't actually _care_ all that much if their neighbors can read yahoo mail or not.
You could also with countries whose access is limited to one or two points threaten them economically.