Growing up I often looked at things through a different lens than most people did. I liked to find things that were odd when taken at a high level and for their very literal interpretation. One of those things was the phrase “skinny.”
Now, let’s look at how the english (well, american english) language works. When something is in excess we at a “y” to it to emphasize the quantity.
When someone is really fun they are funny.

When somone has a lot of hair they are hairy.

When someone smells excessively they are smelly.

With this in mind I could only come to the conlcusion that someone that has a lot of skin is skinny therefore fat people, or tall people for that matter, are skinny.

Next time someone says you are skinny tell them to shove it.