Earlier quoted context omitted.
Except if you actually read and understood the link, points #1, 4, 5 aren't a concern. Moreover, points #2, 3, and 6 apply to just about every piece of software used.
what percentage of FF users on the planet do you expect could read a paper on differential privacy and actually verify those points, while understanding all the ifs and gotchas, and be able to tell if any of the arguments are wrong? What percentage of that elite group would actually be willing to devote the time and energy, for free, for every one of the thousands of softwares they use?
This is true for the user, too. If the only viable choices are 'verify claims at great cost and no gain every few months', or 'use some other privacy-respecting browser', I am going to recommend the second.