Apart from being one of the rare movies about cavalry combat this movie depicts a very interesting problem: The soldier who can´t kill. This is interesting in many ways. Sure it is commonly acknowledged that killing at war and killing in peace time is not the same. While one qualifies as simple killing, the other is said to be murder. You never hear anyone say about a soldier that he “murdered” enemies. He killed them. No judgement here, just a fact. Now what about the soldier himself? Is this really just “killing” for him, a justified way of taking someone else´s life? I don´t think so. Many soldiers suffer from nightmares when back from war and often, one of the elements they dream about, is the enemies they killed coming after them. Undoubtedly they feel guilty. Pacifists all over the planet will agree with them.
Dave in The Lighthorsmen is a good hunter in civil life. He knows how to handle a weapon, he is able to aim and shoot. But he is incapable of killing.
You don´t see that very often in war movies.