Mozilla isn't doing anything to Firefox. The Anonym purchase you linked to was literally to acquire a technology they developed which would, if implemented web-wide, end the dystopian nightmare of privacy invasion that is the current paradigm where a few dozen large companies track everything everyone does on the internet all the time. "Privacy preserving" isn't just a buzzword in that article - privacy is actually preserved, and the companies involved (including Mozilla) learn nothing at all about you - not your name, not an "anonymous" identifier, not your behavior, nothing. Moreso, Anonym didn't just create this technology, the entire company was purpose-founded to create this technology.
There's a lot of misinformation floating around about Mozilla in particular at the moment. Very little of the animosity they receive is truly deserved once you dig past the narrative and find out what Mozilla's actually up to, and why.