When the Americans show their respects to the national flag and sing the anthem, they put on their palm on breast.  That means they are respecting victims who were killed at the independence war.  And if it were not for them, the current US would not exist.  That is why the Americans respect the national flag and anthem, and they are the symbols of independence.
          Most of the Americans respect them, but on the other hand, the percentage of the people who do not respect the national flag and anthem is relatively high in Japan.  Here are interesting results of questionnaires.  A Japanese professor asked two questions to 300 Japanese people if they knew what the national song was.  The answer was: 50% answered "it is a song of the Emperor.", and 30% did "I don't know."  Another question was whether they knew the phrase os the song.  37% did not know at all, 36% knew all, and 17% knew less than half.  Those results indicate Japanese consciousness for the national song is very low.  There is a word concerning the Emperor and admiring the generation.  Today, the Japanese constitution states the Emperor is the symbol of Japan but does not say the current song is the anthem.  While the constitution says so, it is described the anthem is the song which we sing now within only one page of the textbooks used in schools.  The song was made in 1880, actually it is said originally it came from the old song book, KOKIN SYUU, by the government officer of the Imperial House Hold Agency related to the matter of the Emperor.  And it became to be sang at  ceremonies in 1896.  In 1880, the Emperor had absolute power, and the nation had to respect the Emperor.  But as I already described above, the Emperor is a symbol now in Japan, so there is a discrepancy between the old consciousness and current one.  Above all things, Japanese constitution assures the freedom of thought and belief, so the Japanese consciousness for the anthem is low.
          The nation flag is also the same thing.  The nation had the territory already when the current flag was made, and that means it is not the symbol of independence or the acquisition of the land which exists now.  The flag was used when Japan invaded some Asian countries.  Japan has not been invaded, nor has Japan got independence.  It is understandable that many Japanese think the flag is the symbol of the aggression war.  After the World War II, Japan did not make clear statement of the national anthem and flag.  And they are still being used as they were.
          In the past, many countries including the US were involved or invaded, and fought  for their independence.  The national anthems and flags were the symbol of their independence for these countries, but Japan has a quite different case for the reasons stated above.