Invader Zim was arguably the most bizarre kids show of the early 2000s. From depicting an alien harvesting students' organs to appear more human to having an extremely creepy hobo kidnapping kids, this cartoon was jam-packed with macabre elements.
One of the strangest plot points on the show was that everyone except Dib was completely oblivious to the clearly not-human Zim and his alien ways. They were grade-A morons, not to mention disgusting, which didn't paint humanity in the brightest light.
Reddit user yay855 proposed a theory as to why humans on Invader Zim were always clueless idiots: They're seeing Earth through Zim's eyes.
Zim is above everyone else.
Every earthling, minus Dib, is seen as a lesser form of life. This is partly due to Zim's Napoleon complex, since short Irkens are seen as second-rate citizens, but it's also because Irkens have technology lightyears ahead of ours. In order to build himself up, Zim needed to tear down everyone around him.
Humans are just as gross as the food they eat.
Zim sees people and their food as repulsive because the Irkens' food supply isn't overloaded with grease like the Earth's food. Plus, the Irkens "likely live in a much more sterile and orderly environment," making any activity on Earth appear disgusting and unsanitary. Take Chickenfoot or Turkeyneck, for example. Neither appears incredibly hygienic, but they probably don't actually look like that — it's only how Zim perceives them. Since the camera lens is through Zim's eyes, that's how we're forced to see the population, too.