I think that is just a necessity considering how long of a period of time this video spans (from the medieval period that you mention, well into the modern age).
If you were making a similar animation that spanned the last 1000 years, how would you suggest presenting it? Are you saying it would not be possible in any meaningful way? Is there an arbitrary date that you would pick that it would begin to be meaningful?
Political border maps fundamentally rely upon our modern preconceptions of nationality and nationalism. No matter how hard you tried, it would always invoke those kinds of concept and all the baggage that goes along with it.
It is not meaningful in the same way attempting to translate Chinese visual poetry (depending on the form and shape and even history of their letters, to make puns and allegory etc) is not meaningful.
The two concepts are just simply not compatible.
"So you have told me about the halting problem, great, so how can we achieve flawless static analysis?" ;)
If you were making a similar animation that spanned the last 1000 years, how would you suggest presenting it? Are you saying it would not be possible in any meaningful way? Is there an arbitrary date that you would pick that it would begin to be meaningful?