The problem is, so called "anonymized" data is able to identify you (sometimes with very few data points required. Source: https://techcrunch.com/2019/07/24/researchers-spotlight-the-...). Mozilla advertises Firefox as the browser that doesn't track you, but that's just wrong (since FF has quite a bit of telemetry). And it's on by default, and since people who are new to the privacy mindset may not know about how this telemetry is on, it's sad how Firefox is still recommended.