Also been using FF for 2 decades, but can corroborate the experience you cannot.
I have seen all those things he complained about. Diversity initiatives, new features, etc. For me it appears as a new tab on restart that I have to close, and it does feel like it's every single time I update, and sometimes between updates.
It is especially annoying on a seldom-used machine where the browser will typically be outdated every single time you start it up. To make things worse, the machine is rarely used and only gets powered on when you actually need to do a task right away, so the bullshit update notifications are infuriating. I can put up with the updates themselves for security reasons, but intentionally getting in my way for no functional reason is too much.
I have seen all those things he complained about. Diversity initiatives, new features, etc. For me it appears as a new tab on restart that I have to close, and it does feel like it's every single time I update, and sometimes between updates.