Yes, I think that it was justified to use agent orange in the Vietnam War. During war, bad things are going to happen, that is just part of it, and a side will do everything it can to win. America was just trying to get an edge and with the war.
People don't understand that war involves huge-scale destruction of populations, areas, and property. If people go to war, then all measures are often taken to win; this isn't to justify these things, but rather, to show people that this is the reality of war. There were no holds-barred during the war.
There were too many civilian targets hit with Agent Orange, plus our own troops suffered ill effects by the application of the strong herbicide during the Vietnam War. The point was to root out Vietcong sympathizers in the jungle. The move backfired as more people became sympathetic to the North Vietnamese cause due to America's ineptitude during the war. We should have left Vietnam to the French instead of getting involved in the first place.
During the Vietnam War the United States military sprayed more than 19 million gallons of herbicides over 4.5 million acres of land in Vietnam from 1961 to 1972. Given this massive use of Agent Orange I do not believe it was justifiable. Additionally, Agent Orange was used to kill crops and starve people which would have obviously affected women and children.
Without a doubt, this situation is arguable for both sides. Each side must remember that they need to compromise with the other side in order to bring about the most preferable solution. Otherwise, leaving one party in the dust can lead to problems later on. Compromise is always the best solution.