About four months before this cartoon appeared, a teacher was shot dead in a Minnesota public school. The preceding ten years had seen six shooting incidents in schools resulting in six deaths and one injury. These are certainly not as severe as have been seen in recent years, but that may be largely because of the advanced weaponry now available to shooters. For an individual to do much damage in those days required not only guns but explosives, lots of explosives, and required days of secret on-scene work to implant explosive devices.
On May 18, 1927, in Bath Township, Michigan, guns, bombs hidden in the school, and a truck loaded with shrapnel and explosives were used by Andrew Kehoe to kill 38 elementary schoolchildren and six adults. At least 58 other people were injured.
So, massive and insane murderous acts were not unheard of a hundred years ago, they were just more difficult logistically.
This cartoon was published about four and a half years after the Bath massacre. It’s puzzling to me how this could be the stuff of humor in a daily comic strip of the day.