>you can easily disable it just as you can easily disable many other things that Firefox includes by-default

>it would be nice if Firefox actually packaged Pocket as a real extension that could be removed from the Extensions menu

These two statements you made seem to corroborate his characterization of it being "opt-out" (meaning on by default, but capable of being disabled) and "non-removable" (baked into firefox as opposed to an extension). Not sure what you find wrong with his characterization.