Could also be a correlation due to people who actually get diagnosed with dyslexia/dysgraphia being more likely to live in places that are more affluent or with better mental healthcare.
That would tend to correlate with generally more accepting populations.
I loved FFSend. When it died, I ended up standing up a GOKAPI server, as it was the closest alternative I could find at the time: https://github.com/Forceu/Gokapi
Definitely not as nice as FFSend though. I may have to give that fork a try instead.