It could be that everyone in the US is self-centered and thinks the world ends at the edge of North America. Or perhaps the executive producer who was quoted simply didn't know of these shows and made an honest mistake.
Well, they could also titled it "The Longest-Running Kids Animated Series In US". Naming it the longest animated series in history implied that there is no other animated series produced all around the world, which run longer than it.
It could be that everyone in the US is self-centered and thinks the world ends at the edge of North America. Or perhaps the executive producer who was quoted simply didn't know of these shows and made an honest mistake.