Different countries, different histories, different legal traditions. Scotland is a nation in the British Commonwealth, not a province (shire) of the nation of England. Aragon and Catalonia did not follow the same pattern.
If you look at a map you will understand the reason for why spain wants to hide and prevent a referendum.
Again, if you believe that fantasy is true, is impossible to open your eyes to reality.
Please, point to a reputable source.