Bad, bad Mozilla! For me, personally, it's what makes this model so fallible and not developer / community friendly. What if, tomorrow, some country blacklists the Firefox website, and one still needs to load some privacy extensions? This is exactly the sort of usecase Firefox should allow, if it's pro privacy.
Add-ons can still be installed from outside addons.mozilla.org, as long as they're signed (an automated process), or you're using something other than an official stable-channel Firefox build and have unsigned add-on install enabled.
The announcement in question pertains to a specific method of silently force-installing unremovable add-ons to Firefox.
