I very much agree. Growing up in central California with a very diverse population, including a multitude of 1st and 2nd generation Japanese, I can honestly say cultural differences can play a huge role in ones appreciation for different things. Japanese and White Anglo Saxon Protestants both eat Sukiaki. WASPS think it special, but in Japanese it is still "Beggars Hash".
Art is much the same, and Koi is an art form.
Japanese art has a look of its own that a typical American can enjoy but have no clue how to critique or understand its cultural significance. Japanese can look at a work of art and tell you what it means and why, but it probably won't help you understand the significance of the next painting. We only know if we like it or not, not what it communicates.
When a typical American (or anyone else in the world outside the orient for that matter) view a koi we see beauty and physicality and if we judge it we generally do so on technical merits influenced by eye appeal. The Japanese will see an expression of art derived from their culture and its form will communicate something that goes beyond technical merit or eye candy. Unless we eventually succede in corrupting Japanese Culture (god forbid) that distinction will remain.