Once again, this post is off of the topic from this thread. There are plenty of other threads that discuss the issues that you are bringing up.
If you wish to further debate the notion of using blunt force trauma (aka "whacking") as a humane method of euthanasia, contact the American Veterinary Medical Association and explain to them that you disagree with their findings.
Feel free to add anything about HUMANE euthanization using CO2 gas. Thanks.