I figure he is jealous. Rather than develop an understanding of how historical weapons work, what it took to load, fire, carry them, understand their lethality, he wants people to spend their money on his latest book that will tell them what he as an historian has determined they should know about that subject.
Some people think history is a study of the past. Marxists think history is what they tell people.
With reference to the Civil War, you are perfectly right, the weapon technology of the time dictated tactics and tactics dictated strategy. And so we have the tactics of men lining up to mass firepower causing huge casualties. We have those tactics dictating strategy which ultimately led, for example, to Lee's invasion of the North or Sherman's devastation by fire on his march to the sea.
In turn, these strategies of total warfare devastated the South for generations and led to a disparity in economic progress, Jim Crow, segregation, and civil rights struggles.
The professors' disdain for tactics, for the study of the blood and mud of war is to lose a very valuable perspective and to teach a distorted history.
After researching the real Lincoln, I think all of these academics are frauds. I call it the Lincoln fairly tale. Reconstructed BS....