I wonder how long it'll be before Firefox comes with it enabled by default. It seems that they're going to do it regardless of the loss of control implications to end users.
That seems to be a common trend these days --- ignore what they want, claim that it's "for their safety/security/privacy/whatever", and gradually remove options for configurability.
In particular, this sort of "overstepping the boundaries" is unfortunately getting more popular, and IMHO it's rather disturbing that browsers have gone in this direction; software should follow the system defaults/configuration whatever they are. Yes, the platform coud be compromised or otherwise not to your liking. That's not your problem, Mozilla!
(I run everything on my network through a filtering proxy. These attempts to subvert it are definitely not welcome.)
It so happens that many of the people who post on this site actively administrate at least a home network for which they are also end users. But even in that rarified group, how many people don't connect their computers to untrusted Wi-Fi networks, regularly or at least occasionally? I'd guess it's a pretty low fraction. And among Firefox users in general, the fraction that has meaningful input over the configuration of any network they connect to is surely negligible. (Owning a router doesn't count if you don't know how to configure it.)
If you're really an end user, then you'll always have the ability to change Firefox's settings to turn off DoH, or point it at whatever server you want. It's only if you're trying to monitor someone else's connections that you're out of luck.
But will you, even in a year or five from now? And in the broader discussion of DoH-in-browsers, will the same be true about Chrome?
(I believe the answers are "maybe" and "not likely", respectively.)
Is this like a DHCP option or RADIUS attribute to supply DoH IP/Hostname?