What the hell is Mozilla doing? If they want to protect peoples' privacy, they need to ship Firefox with an adblocker by default, not ask people to install spyware to surveil ads.
Firefox already blocks ads (via the "Tracking Protection" feature: https://i.imgur.com/Z3050xN.png ). Does it block as much as an addon like uBlock Origin? No, but stuff like Google Adsense or Analytics should be blocked.
Blocking ads by accident isn't an ad blocker. I'm glad the "Tracking Protection" feature is there, but it isn't enough.