Louis did everything he could to avoid taking innocent lives. In fact, I think it is very late in the series when he aquires the ability to begin to distinguish between an appropriate victim and an inappropriate one.
Rice plays around a lot with questions of moral ambiguity in being a vampire.
For example, we find out in The Vampire Lestat that Lestat is a telepath, and makes a habit of only killing victims who have demonstrated prior evil. We also learn that he was an unwilling victim of vampirism himself. Often his subjects are willing in the story. It also turns out that after reaching certain ages, many of the restrictions we normal accept about vampires go away. Imagine hunger with a asymptotic curve.