https://developers.google.com/speed/public-dns/docs/ecs
https://developers.google.com/speed/public-dns/faq#locations (when EDNS0/ECS isn't supported)
The tin foil hat brigade might suggest that this is deliberate to ensure that only what's served by cloudflare gets to be fast...
Conspiracy theory isn't a dirty word.
Speculation keeps people informed and alive.
https://developers.google.com/speed/public-dns/docs/ecs
https://developers.google.com/speed/public-dns/faq#locations (when EDNS0/ECS isn't supported)
The tin foil hat brigade might suggest that this is deliberate to ensure that only what's served by cloudflare gets to be fast...