Maybe it won because it paints Africa in a positive light? Africa is a gorgeous continent and considering how vibrant and beautiful the backgrounds are, tlg does a lot to reinforce that. A lot of western news does not give such positivity, most Americans probably don't even know there are a lot of big and thriving cities there.
Just two years ago there were ebola breakouts, many died, and American news outlets really didnt care until it hit America. And here's a show that actually gives a crap about Africa.
The show also teaches about Swahili, a language unseen in any other western cartoon.
While it does feel a bit too British at times, it's still way ahead of the curve compared to every other tv toon set in Africa. Which uh....isn't a large number.