I don't think Debian "objected". Mozilla's trademark rules are not compatible with the DFSG, therefore Debian can't distribute an officially branded Firefox. I do think the ideal thing would be for Mozilla to distribute Firefox packaged in such a fashion that the branding can easily be swapped out (in the same way that e.g. Redhat isolates its trademarked material to a couple of packages and documents exactly what you need to replace if you want to distribute your own modified version of Redhat) so that there would be no need for a full fork.
1. It's true that the Debian didn't initiate the schism. Mike Connor (Mozilla) told the Debian folks to stop distributing branded builds that weren't QAd by Mozilla.
2. When doing a build, it has always been trivial to create an unbranded version. Unbranded versions are what you'd get by default. At this point, I haven't run a build in years, but it would be surprising if this weren't still the case.
I don't think it's the case anymore. They used to name the releases and then brand it based on the name. The releases are treated as inconsequential now.
