The correct answer to this open question is the following.
What Richard Tobin meant by his statement, "The veneer of civilization has dropped away," is the following.
British official Richard Tobin was talking about the terrible war in the trenches during World War I.
What he meant was that when soldiers fought in the trenches, that was the jungle, like animals fighting trying to survive.
To better comprehend this idea we have to say that in those years of World War I, the zone between trenched was known as "No man's land," meaning that in order to survive, everything was possible. And the fight was cruel, bringing the worst out of humans. And in that time, if the army wanted to occupy the enemy's position, the only way was through breaking into the enemy's trenches. Soldiers did not though or reason, they just reacted and attacked, like in the jungle. It was only a matter of survival.