I've done a lot of research on North Korea. The people in that country are fed a constant diet of propaganda from the day they are born. They are subjected to regular shows of patriotism, grand parades, massive rallies and steady streams of misinformation. Most North Koreans outside the capital live in desperate poverty and misery, while those who are lucky enough to live in the capital (mostly military members and their families) are never told about the dire situation in the rest of the country. 

By building up a military presence in the region, the U.S is only making a volatile situation worse, and giving North Korea more material to use in their propaganda machine.