Was it hypocritical to mourn the death of fifteen people after he had already killed many times that number with his own hands? Regardless of enemy or friend, innocent or guilty, evil or good, was one life worth more than the other? For Sturm, there definitely was a difference, but it had nothing to do with worth but survival.
The guards and slavers back in the slave camp had not only frequently abused their power but had tried to kill him. If you plan to take someone else's life, then you have to be prepared to give up your own in return. It was a simple truth and how the world, especially this one, worked.
That did not mean others did not deserve to die, but Sturm had yet to kill someone on purpose without acting in self-defense. For some time, he thought he was cold-blooded for not feeling too much remorse, as their deaths never gave him sleepless nights.