It has nothing to do with being humane and everything to do with appearing humane and, even more importantly, avoiding association with otherwise extremely simi

It has nothing to do with being humane and everything to do with appearing humane and, even more importantly, avoiding association with otherwise extremely similar killing. Shooting prisoners in the head would be humane, but it would invite comparison to terrorists, revolutionaries, and other unsavories. However warranted the comparisons are, dressing up executions in medical nonsense avoids them, so our government does it.