I'll keep avoiding firefox as long as they keep pushing weird decision with each update, the latest one being forcing "pocket recommendation" on the new tab page, even if the built-in (that is, you can't remove it) pocket extension is disabled.
Sure, I can go look for the new advanced parameter to disable every time, but why pull this shit in the first place.
You can, but there's a big difference : the average user (=the vast majority of people) will not see the difference. In some tech circles, or if you're actively looking for it, you'll know that it happens, and what it might (or might not) do, but 90% of people will not see a change. User interface remain the same, features remains the same, and extensions that could adapt will already have done so.
Firefox choices, for better or for worse, are very visible. The pocket extension was bundled in it, making it so that everyone have it show up one day. It being named after a (formerly) third-party service is not a good look. Then the new-tab page suggestions, which I can only see as an intrusive way to push content onto me (something I actively try to avoid, the samy way many "social network" keep pushing what their algorithms think is good for you). Add to that some decisions about actively ignoring user settings (and page content) about PDF handling, subsequently breaking tons of SPA because "they know better" (there was a long discussion, and the change was half-reverted once big enough sites showed issues).
The list could go on, ranging from "interesting" UI choices to bundling more and more advertisement for their own service, only to backpedal later with "oh, we didn't think it would annoy people to do the exact thing you're running from other browsers for".
Chrome changes might be insidious, but they have limited impact to the actual users. Mozilla keeps changing Firefox in very glaring ways and not always with a sound reasons, user-wise. One could argue that these changes are all minor, but they do act as a deterrent for people that really can't handle changes (remember, for most people changing the icon on a button is enough to make a feature "disappear" for them).
I'd argue crippling what ublock origin is caple of doing is very crippling to the end user experience. Accepting a cippled ublock is similar to accepting the change when adblock plus white listed some ads.
Again, factor in the number of people knowingly using ublock, and actively looking into what changed vs. what still works fine for now. Manifest v3 have no reach beyond techies, and as such is "accepted" by default.
Remember that most people are totally fine with these changes because the larger picture is not shown to them.