Aber, I beg to differ, individuals involved in any killing do feel regret and many of the lads suffering PTSD prove that point. The fact you have not been in that type of environment does not mean your point is any less valid but you cannot make a generalisation based on your belief alone. I know ex-servicemen who have spent 22 years in the forces and have never been to an active ware zone. Equally many have been to active zones and never shot a round in anger or indeed never been that close to the action. Modern warfare has meant less hand to hand combat or trench warfare. Your points of reference are historic and do not take into account the differing climates at the time.
In my opinion the anarchists (who as you say are a minority) would be just as bad as current governments if not worse as they will have to fight to keep themselves in power. The only way they could do that is to either spy on the people or oppress those they feel are a threat. That much history has taught us through the actions of Stalin, Hitler, Chairman Mao etc, etc....
You cannot compare the Nazi movement with the situation today. The German people at that time were suffering because of the 1st world war and the draconian measures of the Versailles agreement. Hitler was an extremely persuasive individual who tapped into the mind of all Germans based on their struggles. He brought his own like minded people and sycophants into power and that's when the real evil began. He did unspeakable things to his own people as well as the jews, gypsies and political activists long before the 2nd world war.
There are disaffected people out there, and believe me it includes a lot of ex-servicemen, that do not like the current government nor that of Blairs regime but they took the Queens shilling and served their country Welsh, Scots, northern Irish and English alike. Politicians may not regret the deaths of innocents but the vast majority of servicemen do.