The problem with Latin America, actually, is the fact that no one wants to set up local servers here.
For example, Netflix released their service here. Did they put a Netflix CDN box in every street corner like they did in the US? Of course not. They're just saturating the already busy international pipes.
MaxCDN, one of the most well known CDN services, do they have servers in Latin America? From what I see: No, they don't. We rely on US servers. At least that's what I noticed when using the Bootstrap3 CDN, which uses MaxCDN: it was faster for me to serve the library from my own host than using the CDN.
Now, other big players have set up servers. Many years ago Youtube set up a local server for Cablevision users in Buenos Aires (serving all of Argentina). Youtube is the only streaming service that works fine.
Amazon has local servers. My business website is hosted on EC2 in Brazil and it's VERY FAST. It's less than 60ms away so it feels really snappy.
Facebook has shown zero interest in serving users here. They have gladly set up offices everywhere to SELL ADS, but they haven't bothered to set up any datacenters here. And, of all services, facebook DEFINITELY SHOULD set up a datacenter here. Facebook isn't bandwidth hungry, but it definitely needs low latency to be responsive.
And this is something that bothers me, honestly. I'm all for net neutrality, but this is really an abuse of net neutrality. Netflix is investing ZERO for providing service here. They charge the same amount as they charge in the US, but their service is lacking. They don't bother serving content locally and just saturate the pipes ISPs here can barely afford. My ISP has to pay more to serve a few Netflix users and this is reflected in my bill.
So, answering to your points:
A) Maybe Argentina has problems, but I have a friend in Colombia who's also complaining about the HORRIBLE performance on Facebook.
B) That's an issue the US Embassies around Latin America should fix. Push for legislation around this issue (since US embassies do this all the time, they might as well force stupid ISPs here to behave).
C) This doesn't make sense. Of course there's more demand from LATAM to the world, since everyone's servers are outside. If big companies (Google, Facebook and some of the larger CDNs) placed their servers here, it would be a completely different story. I've run tests on smaller ISPs and found that 80% of traffic, by volume, is Youtube. If Google sets up local caching all over these countries the pipes "get unclogged" really fast.