The Eastern Front of WWII was literally the largest military conflict in human history.
I don't know if Patton would have come to a second opinion if he had lived long enough to learn about just how ferocious the fighting between the Wehrmacht and the Red Army was. I'd like to think that he would have.
I always took any criticisms of Russians by Gen. Patton to be directed at the Communists, not the people themselves suffering under their totalitarian genocidal misrule (which, unfortunately, a few senile idiots around here believe that Russia is still Communist to justify their hatred and warmongering - hint: it’s not).