Lack of ruthlessness?
The Russian army and air force have demonstrated a surfeit of ruthlessness. The mass bombardment of the city of Kharkiv for instance, with indiscriminate volleys of thousands of unguided 220mm Uragan rockets.
Just one case out of an endless litany.
Aside from SBU/ Banderite murder of Russian ethnics, and nine years of indiscriminate khokhol terror attacks on the civilian population of the Donbass (in addition to the widespread terrorism in the 2014 Obama revolution), civilian casualties at Russian hands have been quite restrained- and on a level magnitudes lower than the casual death and destruction that is USA military standard practice in nearly all conflicts since at least Bush I/ Clinton.