[Nyororin]

I have found that Japan is patriotic, but at the same time taught that being patriotic is a bad bad thing... So it causes this sort of strange internal stress.

People are naturally patriotic. There are degrees to it, of course, but people will naturally have a love of home, family, and as an extension - country. Whether they realize this is another subject altogether, but the natural tendency is there. This is a reason it is so common to see expats who thought they hated their home countries becoming extremely angry when someone else criticizes their native country.
When the culture supports patriotism, like the US, it is simply a normal thing and you see it a lot in the forefront.

In Japan, people have this same tendency to be patriotic... But patriotism was very strong during the war. After the war, it was presented as one of the reasons for the war, and put into the taboo box. Being patriotic came to mean being very right wing and wanting war in the public psyche. People seem to have been taught that it is better to behave as if they think very negatively of their country.

So you very rarely see displays of patriotism in Japan. The negative connotations of public displays of patriotism are just too large.