They shoot horses don't they? I thought doing that meant showing mercy.

After beating back the insurgents with the help of a US attack helicopter, the Canadians came across a seriously wounded Taliban fighter, who was disarmed and judged too injured to provide medical aid.
The court papers found that Semrau was the only person near the wounded insurgent when two gunshots were heard. At least one witness said they saw Semrau fire his weapon on the wounded man.

I am in a foul mood today. I thought our soldiers were there to kill the bad guys. Clearly, this bad guy was going to die in agony, and the soldier took mercy on him and sent him to his harem made up of 70 little boys and girls, a few minutes ahead of schedule. So, tell me, why is this soldier treated this way by our Canadian so called "legal" system ?