Except even that answer makes no sense since VLC implements time-based seeking which has the same requirements as seeking to a specific frame number. The only additional part to implement is automatically skipping forward a number of frames after the closest preceeding seek point.

Adding a requirement of supporting this perfectly with literally all formats you can think of is not reasonable at all since a video player that stuck to that principle would not be able to support any controls at all. It's the kind of bullshit excuse developers or corporations like to give when they don't want to implement something but also don't want to be honest about that.