I live in Australia, and when I was growing up I thought the same, even though Indonesia are a very close neighbour of ours. Indonesia is featured quite a bit in our local news these days, and that together with lots of Aussie tourists in Indonesia, plus lots of Indonesian students studying here, has made us a little more knowledgeable about our neighbours.
This doesn’t fall under the category of basic geography. I can guarantee you that the majority of people you attended school with would not be able to locate Indonesia on a map, much less tell you about the religions practiced there.
I checked them for a few nations where I had solid on-the-ground knowledge, and the ranks and full-profile descriptions are straight up false. Usually propaganda involves lying by omission or hyperbole. In this case, it is just wrong.
It goes: Indonesia, Pakistan, India, Bangladesh & Nigeria, in that order.
I suppose it shouldn't be too surprising though, I mean Christianity sure as hell got around too.