Earlier quoted context omitted.
This is nowhere near enough though, and it used to be even worse. Basic spyware such as Google Analytics could be blocked by uBlock for ages and yet it's only recently that the built-in Firefox solution started blocking it (by replacing it with a neutered shim). Furthermore, considering uBlock Origin and the underlying filter lists are available under a permissive license, what's the point behind developing & maintai…
You have to realize Mozilla does not have the marketshare to do this. Most of the web relies on ads, and since uBlock Origin blocks them, there would be no incentive for those sites to support Firefox. Even if you just blocked trackers (as does ETP Strict Mode), many ads get blocked because those ads bundle tracking code within them. This, again, would cause there to be little to no incentive for most website owners…
Over a decade ago, one of the best things that Firefox did to compete against IE6 was to include a built in popup blocker that was on by default. Exactly the same criticisms were made.
It was called irresponsible and disruptive, since so much revenue came from popups, and horrible flash-based full screen pop-under ads. But I am glad that Firefox didn't let the pleas of the established market prevent them from siding with users.