What is this “humor” thing?

nobody-nowhere:

Today I went to the coffee shop with my sisters, who are not autistic, bless their hearts. It was so inspiring how they could sit there in that noisy coffee shop without getting overwhelmed or having sensory overload. My younger sister was even able to read without being distracted by the background noise and conversations. Wow! My non-autistic sisters are so brave and courageous and intelligent!

Cure allism now!

[/sarcasm, inspired by a post I read in the #autism tag.]