I supplied the Texas link and a quote but you clearly didn't open it.
Trial ?? The case didn't get past a grand jury. No charges were laid against the Good Guy for killing a 9 year old child.
""The grand jury, a random group of ordinary people in Harris County who answered their jury summons, heard the evidence in this case as presented by our prosecutors, heard all of the possible charges - from murder to manslaughter to aggravated assault to criminally-negligent homicide."
You are merely pursing a nonsensical hypothetical here.
"Why deny it based on some silly evasion?"
I will never be in a US Mall relying on a Good Guy with a gun for my protection so on what basis can I praise your heroic shooter ?
That's not an evasion, that's a fact. I have no experiential basis on which to judge your Good Guy.
So, your definition of a Good Guy is simply one who is lucky enough not to cause any collateral damage to innocent bystanders.