Its literally a public network where people chose to post things publicly for anyone to see and consume, I don't understand what degree of privacy people are expecting? If you have some insight into this or your own privacy concerns I'm super interested cuz its left me baffled.
I wouldn't stand out in a public city centre and expect privacy. However with the fediverse at least I choose which city centre I'm standing in and if I still don't like it, I can stand in my own and block anyone else to access it (yay privacy :D).
Also reddit served 'targeted' ads, which were admittedly pretty pants, so they had some degree of selling access to your data to third parties, which the fediverse doesn't have.