[nisse72]

You can add

  "DisablePocket": true 

(and many other things) to your policies.json file. In my case that file is a symlink to a single master copy I maintain outside of the FF installation folder. See https://mozilla.github.io/policy-templates/

[jakeogh]

How about a one-liner to disable it globally via /etc/firefox/policies?

I encourage anyone reading this to try it. Good luck. I wrote a python wrapper to manage policies, and it's -deliberately- difficult and fragile. If I ever go back to the FF codebase, it will be a fork without pocket.