They haven't commented on this, but I don't think they are poking fun at FOX, but are poking fun at the rumors that South Korean companies they outsource to are so deplorable.
South Korea is one of the largest economies in the world, with high standards of living, literacy, and better child labor and work condition laws than many of its neighbors, at least from what I know. It isn't China, and it isn't Taiwan, where conditions can actually be atrocious.
Keep in mind that the South Korean studios and companies are credited at the end of each Simpsons episode anyway, so it isn't like it is some big secret.
That's what I think anyway. Until they comment, who knows.