Isn't that because Dan hasn't open-sourced his project yet
Wrong: https://github.com/pixelfed/pixelfed/blob/dev/LICENSE
and doesn't let anybody else contribute?
Hmm, while there have been 158 contributors, a very small percent were from the other developers: https://github.com/pixelfed/pixelfed/graphs/contributors
This information is pretty easy to look up.
For most people, using https and dns over https (DoH) is probably all that's needed.