1. Chrome, as the dominant browser, drives developer behaviour (devs need to change their websites when Chrome breaks compat). Firefox doesn't have this luxury, so some features like this must necessarily be lead by Chrome in the monopolistic browser world we live in.
2. Referers allow websites to individually track users better, which is bad for user privacy if you are concerned about entities such as Facebook, etc. tracking you. However, those entities are Google's competitors; for Google, Chrome does the tracking, so they have no need of the Referer.
Removing it is "good" for user privacy w.r.t. Google's competitors, and simultaneously good for Google (disadvantaging such competitors).