According to MacPherson, how was war viewed by many young Americans before they arrived in Vietnam?

At first, young americans had an idealistic view of the war. They believed that they were stopping communism for a greater good and that the war is a good effort and wanted to join. They believed it was honorable like world war 2 was. They were soon dissuaded when they saw what kind of a war it was and how it was led and many of them ended up scarred for life.