I don't think the parent commenter is arguing that living in feudal Japan was cool, or idealizing it. They are just saying Japanese history is fascinating, which it is. Just like ancient Roman is fascinating, or ancient Greece, but I wouldn't want to have lived there.
2. Post WWII Japan set the benchmark for pulling its people out of poverty in an astonishingly short period of time.
3. There have always been foreign, exotic cultures people have romanticized. The Romans romanticized Greece and ancient Egypt.