Earlier quoted context omitted.
For additional context, here is the Cloudflare explanation about EDNS client subnets: > EDNS Client Subnet > >1.1.1.1 is a privacy centric resolver so it does not send any client IP information and does not send the EDNS Client Subnet Header to authoritative servers. Cloudflare's requests are of course perfectly valid, with @archiveis actively deciding not to service them.
It has nothing to do with privacy, as the next thing following DNS resolution is establishing a TCP connection which always leaks full IP address to the same person or organization controlling authoritative servers. Basically EDNS is just a convenient way for DNS-based CDNs to provide a better edge node. But this is directly competing with Cloudflare, so Cloudflare invents excuses not to implement something that help…
Depends who runs the authoritative servers - if you hit the authoritative DNS services for most of my domains, you are providing your information to 123-Reg (or, increasingly, Google), if you start a TCP connection, you are providing it to me.