I mean, I think retarmus means that something is so retarded that you can't pronounce retard right because that thing is so retarded that it made you retarmus. That's what I think of when I call something retarmus, at least.
Bro, that girl thought that Christopher Columbus was the first US president. Bro, that's so retarmus.
The Homo Sapiens Retardus is, in short, a mentally challenged (self-centered) and/or physically challenged (collar popping) individual. They are usually frowned upon by other members of the Homo genus.
Michael cannot get a passport because he is listed as a 'Homo Sapiens Retardus' in the citizen-register.
Biologically, humans run off the binary of male and female, so biologically people who identify as neither or anything else are saying that they're not human. Therefore, they are a sub-species under the homo genome (similar to how us humans are Homo Sapiens).
John: "Those people who say they're not male or female are not human by their own definition, they are what are now being called Homo Retardus."
A very, very long time ago, in ancient Rome, one man was named this by his ungrateful mother. He was bullied endlessly throughout his time at school and nobody needed to call him names as his official name was bad enough. 20 years later, he legally changed his name and surprising to him, everyone was sad because they had no joy in calling him that name, instead, his name was Dave. Because of the mass sadness, he changed his name back to this where it is now immortalized.