I actually don't have much difficulty reading this, with the exception of a couple technical terms I wasn't familiar with. There was a similar thread a while back with a couple different fun examples, albeit designed to show how we read based on the shape of words (not spelling) rather than to demonstrate dyslexia:
You didn't have trouble reading it, because the author deliberately kept the first and last letters the same, and referred to Typoglycemia, https://en.wikipedia.org/wiki/Typoglycemia, which has shown that you can (often, not always) mix up the internal letters and the works are still very legible.
In doing this, I think the creator was specifically trying to make a Typoglycemia simulator, not a dyslexia simulator, since the original quote said nothing about the first and last letters remaining the same.
Imagine what it would be like if almost all the words were ones you "weren't familiar with," which is how it would seem if you had dyslexia and were learning to read.
https://news.ycombinator.com/item?id=222459