That’s the second option: they don’t care.
> This thread in general feels like it leaves Mozilla no room to experiment
If you you’re going to experiment with something that’s going to cause this amount of backlash (and my criticism is that they didn’t take the obvious reaction into account), you show a dialog on first run that tells you what the feature is, perhaps include a “Learn More” link, and have an option to accept or deny. You can even have the former as the default. And do it in your betas first.
Would that still cause some backlash? Possibly. But it would’ve been significantly milder and you would have seen a lot more defence of Mozilla for not doing without asking.
Mozilla in particular is frequently pulling crap like this and getting flak for it. They have to constantly apologise and back track. After a while you’d expect they learned something.