I think the point was Hitler was Fighting a Two Front war including the Russians (Who had Way more Equipment and not to mention Fighting Men).
For every ONE German Soldier that Died Fighting, FOUR to FIVE Russians would die (Including Civilian Casualties)
Total German losses: 5 790 459 killed, wounded, missing
Total Soviet losses: 26 579 242 killed, wounded, missing
The other front included the Americans whom where and enemy that could produce weapons and manpower that could not be Bombed or Matched by Germany...
Point being, Declaring the War was suicide by Hitler due to the fact he could not match his enemies manpower in the long run...