The argument, which isn't entirely unreasonable, is that ICE cars are obviously paying a per-mile usage fee in the form of fuel taxes which supposedly (not always in practice) are supposed to be used to maintain roads. And it works sort-of, since very light cars (which do least damage to road surface) often have good fuel economy so they pay less tax per mile, vs. heavy trucks which do more wear on the road have usually worse mileage so end up paying more per mile in taxes. Not perfect of course, but approximately reasonable.

EVs break this system because they pay zero fuel taxes but are quite heavy (for their size) so they wear out the road like a heavier car but pay nothing.