I always thought that complaint was kind of odd. It's essentially the same as their Search input. Google/Yahoo/etc. are proprietary but Firefox lets you talk to them directly from their browser. Similarly, the code for the Pocket button (component) for where it handles the user clicking the button, along with what it does to talk to the Pocket server, was all in the open and if you build from source you could just remove that entirely. I was more against it for the same reasons I'm against any UI 'upgrades' when I upgrade the browser. The "share this page" button that suddenly appeared annoys me equally as much. Fortunately I can just remove it from the menu but I'd rather Mozilla didn't mess with my UI customization. (I don't know what I'm going to do when I can't use treestyle tabs anymore. I guess move to Pale Moon.)
Mozilla replaced Reading List (which was client-side encrypted and theoretically self-hostable) with Pocket (which is neither). Search engines need search terms to function; Pocket uses user data to support a particular business model.
Reading List was still in development when it was canceled. Anyone who preferred Pocket was free to install it.
Continuing the current revenue model and supporting Context Graph seem at odds with improving user privacy. Pocket isn't now Free Software, but hopefully it will be feasible to self-host whenever they do release the source.
"I don't know what I'm going to do when I can't use treestyle tabs anymore. I guess move to Pale Moon."
I hear ya, being in a similar boat. My hope is that Netsurf ends up being a decent contender here by the time Mozilla kills XUL. Else, hopefully TST will indeed be made possible with Firefox-specific WebExtension APIs.
TST will be possible with WebExtensions. For hard evidence, even the Add-Ons Engineering Manager is working on his own, personal vertical tabs webextension to suss out what APIs we need: https://github.com/andymckay/sidebar-tabs
We may not land everything we need by the time Firefox 57 releases, but we'll get there. If we miss, you have options: you can decamp to Firefox ESR for a few months, where TST will keep working, or someone could theoretically convert TST to a WebExtension Experiment which would work on DevEdition and Nightly builds of Firefox.
That's very good news. TST is one of the few things that makes web browsing even vaguely viable these days.
I've noticed (on the rare instances I'm on desktop, mostly Mac these days) that Vimperator is also borked (only parts of it seem to be functioning). That's another lifesaver to me, and whatever it takes for it to come back to life and/or an alternative to provide effectively similar functionality ... would be peachy.
If I can lure you to another bit of developer / user advocacy, a bit from about 3 years ago on the content management problem:
