TBH, without going into overmuch detail, I wouldn't generalize from my educational experience to the American educational system as a whole. I think it was better in a lot of ways, and worse in a few ways, than what most people would have received, and I wouldn't be surprised if there were some particular holes in my knowledge due to taking part in multiple curricula from different institutions.

Now figure out how Christianity got around in SEA region.

He’s being obtuse, it isn’t common knowledge at all.

> What do they teach in American schools? Apparently not even basic geography?

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.