Not sure where you saw this, as that was also my argument why Flatpak gave "application developers are in control of the release cycle" again instead of this being the packager; they can't perform the same quality control.
They should never package what rpmfusion offers, or distribute a new flatpak when something is already available. That worked when flathub didn't exist or was mostly empty, but that time is gone now.
Note: I want to understand what led to the comment of the C&D-like legal threat.
As for the C&D, the github has some issues with Fedora distros and labeled as "Dependency issues" and there's no indication if the user is using the fedora flatpak or the flathub one, so if I had to guess I would guess that they aren't that happy with:
1. Being asked to fix bugs introduced by downstream.
2. Having their brand damaged because it isn't clear that the fedora
flatpak is a way more limited version than the verified one.
3. Having their issues with their complaints minimized and ignored by
the people responsible for the fedora flatpak system.
The thing about complaints being "minimized and ignored" really isn't true. There is a gigantic thread that's a direct response to their complaints: https://pagure.io/fedora-workstation/issue/463
yes, it recently got unfortunately heated with the whole "whose idea about what to do with Qt is better" argument, but the whole way through that ticket - which was filed 23 days ago, and has had active discussion going that whole time, including being the main topic at multiple workstation WG meetings - it's been pretty clear that the outcome is likely to involve Fedora flatpaks being demoted. The very first post is a proposal - by a key member of the workstation WG - to move flathub ahead of Fedora flatpaks in the precedence order. Consistently through the discussion, catanzaro and other workstation WG members have been supporting that idea, with a lot of discussion and argument about the details, as you always get in F/OSS projects. we do all the sausage factory stuff in the open, that's the point.
They should never package what rpmfusion offers, or distribute a new flatpak when something is already available. That worked when flathub didn't exist or was mostly empty, but that time is gone now.
Note: I want to understand what led to the comment of the C&D-like legal threat.