Whenever there is a war of any kind you can count on each side claiming that they're doing the right thing and they might even believe in it. The problem is the perception of war, even after the war is over. The best example of this problem is World War II, before, during and even after World War II each side claimed that the other side was evil and that it was a treat to their lifestyle and even their very existence. The best way to explain this problem is probably "History is written by the victors".
War facts aren't necessarily what happens or what happened it is what the leaders want you to believe, World War II is an important example because never before was so much propaganda used like in this war. Every major power in the war claimed that they're the good guys and that the enemy were the bad guys, this is an understandable position but it get's problematic when you can't find the real war facts after the war itself ended. Because of one thing or another governments are reluctant to admit that their propaganda wasn't true and for some that isn't even necessary, nobody asks the winners if they're telling the truth, only the losers have to justify their actions.
After World War II came the Cold War and that may be an even better example of the distortion of war facts. While the US and USSR didn't really fight in the Cold War there was a battle of ideologies and because of that both sides heavily depended and used their propaganda machines. The US government made a great effort of convincing the general public of the need to fight communism and while the USSR didn't directly have to do that they needed the people to keep them in power so they did anti-capitalist propaganda as well. As you can see, modern warfare isn't just fighting the enemy with guns and tanks, the distortion of war facts is just as important if not even more important than the battles themselves.