The report gives a quick summary of what they include, but not any details or math.

The cost of underlying energy (gas, diesel, electric)
State excise taxes charged for road maintenance
The cost to operate a pump or charger
The cost to drive to a fueling station (deadhead miles)

Elsewhere it says it assumes 12k miles in a year and is focused on the midwest and Michigan in particular. As it so happens, Michigan charges for registration based on the car value. EVs cost more than ICE vehicles in the same market segment most of the time. This would fall under excise taxes that they include.

I wouldn’t be surprised if they also tacked on the cost to install a L2 charger once as “cost to operate a pump or charger” — intentionally ignoring that it’s a one-time fee to support EVs at a home. With those two data points they could easily add >$1000 to the cost to “charge” an EV for one year if that is what they wanted to do.

The people making the report clearly picked criteria that sounds reasonable but also intentionally misleads people. Not a surprise.