Let's make it easy...*spoilers*
For those of you who think us Americans are stupid let's make it simple.
First we have to decide who is making the changes in the world. That's up to you. Is it God? Is it the "universe"? Is is aliens? We just don't know and the movie gives no hints to this.
Why are the changes being made? People just dying for no reason, Ugandans flying, etc? Because someone or some THING (see above) has decided it to be so.
The people are being punished for wrong-doings (makes me think of some of the many punishments that happened in many religious stories). The world is going the wrong way...will the people stop and then stop the punishments? Who knows?
The Ugandans are more pure and loving people. Whomever or whatever is doing this is trying to take them away from the horrible things that are happening in the world and also trying to send a message...one that no one is hearing in the rest of the world.
So you have the punishment and the reward ... even though the Ugandans were afraid, it's just because no one really understood what was happening yet.
Then you have the love story. I think any idiot can understand that part of the story with the cloning and the horrible family and the attempted escape.
So there you go. Minor Cliff Notes for "It's all About Love".