If you say "no, we're not pursuing this feature because it's impossible" and users have used other software that implements the feature to a reasonable degree of functionality, you're not doing yourself any favours in terms of shutting down demands. You'd be better off either not giving a reason at all, or giving reasons that are clearer to people who aren't as knowledgable.
Reasons are actually stated, they explained it is not feasible for the general case.
Once the devs have made clear they don’t plan to do exceptions (as other softwares do) then users should accept it and move on instead of keep harassing volunteers.
... except VLC implements time-based seeking which has pretty much the same requirements and is consequently not possible with literally all files either. But both are possible with 99.99% of video files you will come accross.
VLC developers are of course free to reject any feature request but if they do it by bullshitting their users (and that includes tacking on additional requirements that no user actually needs like perfect support for all formats under the sun) then they will be rightfully called out for it. Then throwing a tantrum and citing CoC violations is not going to improve things.
It's their project so ultimately they get to choose to run it into the ground but this kind of behavior is not something I want to support as a user os I will stay away from VLC which includes not making helpful bug reports and not donating.
Why is it incumbent on the developers (who know their codebase and its capabilities better than the forum posters) to explain their decision to the forum posters begging for a feature, and not only explain it, but explain the decision and the reasoning behind in such clarity and depth that the forum posters (who might not even be programmers, let alone know the code base) understand it sufficiently well to refrain from begging and insulting?
Because - and more so for the maintainers/managers of those projects - being able to communicate effectively is part of what it means to run a successful project?
That may even mean that you have to hold yourself to a higher standard than some low-effort post on the part of some casual user. Especially if you're the boss, the maintainer, the leader. And if that's asymmetric then yes it is - but to be a maintainer/manager of a project is also asymmetric. Good managers might also promote that culture more widely across all the project's contributors and so yes it may apply to all developers, too.
Not everyone that engages with your project is going to be perfect, some may even be rude. But as a representative of that project it's a skill to be able to cope with that, on behalf of the project (not you). I think one of the most underrated skills of a FOSS maintainer is a degree of fault-tolerance, to use a systems analogy.
Or, you could argue that no, it's not incumbent on a maintainer to be anything, even to be kind. But then don't expect your users to come back.
