I believe it does. Weakly reciprocal license like LGPL is not equivalent as a permissive license like Apache. I see two main things on the top of my head:

1. This ensure that no one can license wash ffmpg and e.g. use rockchip’s repo to distribute their own private product based on ffmpeg without publishing their changes
2. It ensures proper attribution of the work, which can have an impact on the developer’s careers and ffmpeg as a whole.

On top of this, it really should not be complicated to license this code properly (unless rockchip wants to allow point 1, which is illegal)