The Mr. Robot extension didn't send data about you to other people so that means it didn't invade your privacy. It was strange that Mozilla would allow such an extension but it wasn't spying on you.
Blocking ads that target us is the main reason we notice privacy invasion. The Mr. Robot extension was an ad, and Mozilla received money to distribute it to their "hacker" base. How is it not an invasion of privacy?
You're conflating different forms of ads. Ads that get your info through trackers are invading your privacy. The Mr. Robot ad is as invading of your privacy as an ad in a paper magazine. It didn't collect your data. Come on don't pretend you don't know how invasion of privacy works.