There was a long period of time during which firefox users weren't sure whether they were going to follow chrome (like they did on every single other thing.) They're still user-hostile and their values are inscrutable; I have no trust that they won't kill ad blocking next year, or the year after. Requiring add-ons to be signed was a more radically hostile leap than moving to ManifestV3 would be.

The people still complaining about firefox are its most faithful users. The reason some are vicious is because they are trapped - they'll consider cutting their use of the internet before using an non-FOSS browser. 90% of firefox's users left. People who could stand a closed browser have already decided to use one. You're in an extreme minority if you even know anything about firefox to complain about. This year the Linux desktop, of all impossible things, has become more popular than firefox.

Yet there's still this confidence and attitude about even the remaining users that comes from being spoon-fed cash by your direct competitor in return for nothing.