And that naïve artist somehow managed to create a work that follows Zipf's law, 4 centuries before it was discovered?
It also applies to a range of natural phenomena, e.g. lunar craters and earthquakes: https://www.cs.cornell.edu/courses/cs6241/2019sp/readings/Ne...
So the fact that word frequencies in the Voynich Manuscript follow Zipf's law doesn't prove it's written in a natural language.