Soldato
Nagasaki was not a pre existing city in the 16th century. It was a small fishing village until the Portuguese founded their port and the city grew around that in 1543. By 1549 the Jesuits had founded a Christian mission and began to spread Catholicism throughout Japan.
It was not 1637 that the shogunate outlawed Christianity and during the Meijii period from 1868 the spread of churches and Western European influence gained popularity once again. These events and the western architecture relating to these events is why Nagasaki has been submitted for Unesco Heritage site status.
You are correct with the Sakoku policy under the Tokugawa Shogunate where all foreign trade and contact was banned, with the exception of the Nagasaki port.
Indeed, no-one is questioning their immigration policy, just pointing out that their culture has been significantly influenced from other outside cultures, in particular Western ones over the last few centuries.
I have been to Japan 7 times in the last decade. Including Nakasaki.
Their culture is their own, just as ours is our own, however it is heavily influenced by western and in particular American culture which if you have visited yourself you would know.
I will say that the best part of Japanese culture is the fact that it is deemed very rude to use mobile phones and having loud conversations on public transport, a pet hate of mine.
What is this? A game of Mastermind, subject Japan?. Shouldn't we be getting back on topic, about riots in our own country? Well at least my own country by birth.