I’m curious how people feel about wanting the Tor browsers to override system DNS for privacy but Firefox doing it for privacy is totally unacceptable and should defer to DHCP.
In Tor browser I want every request bundled and bounced through Tor. It is a special exception. Non-special-case software should respect my OS and network's DNS settings. Simple as that. I shouldn't have to fiddle with network settings in each application to get it to behave the way I want. Seems fine that it's there, if people want to turn it on, but it should not be on by default.
With tor it's required because otherwise any privacy benefits (literally the point of using tor browser) will be negated by dns leaks. On the other hand with firefox it's not required, and the privacy benefits is debatable since the queries just get funneled from one corporation (your ISP) to another (cloudflare).
Trust. The same reason you'd trust someone with a driver's license to operate a car over a toddler. Tor is privacy and anonymity protecting software. Firefox is a web browser.