Indeed! When describing a chain of events, it is easy to nitpick on link several steps removed from the POD based on what happened without the POD taking place. The whole point of alternative history is the cascade of changes that take place after a POD.
If the Germans had more resources available when they came to within sight of Moscow, they would have been able to actually attack it, and possibly they'd have conquered it. In any case, that would have caused problems for the Russians that the Russians would have had to deal with, such as moving the political leadership elsewhere.
Stalingrad did not need to be taken. The Wehrmacht could have cut off river transport on the Volga upstream or downstream. After a relatively short siege with no supplies coming in, Stalingrad would not be a place from which Russia could launch any offensive actions.
Likewise, the loyalty of the Red Army to Stalin was based on fear. Fear-based loyalty is the most transitory of all loyalties. One cannot assume that because the Red Army was loyal to Stalin in our timeline that it would remain so in other time lines.
By a similar token, it cannot be argued that Red Army troops would mutiny and turn against the state, but it is reasonable to postulate that they could become demoralized and would fight with less enthusiasm, which could change the outcome of battles.
And even if the Asian republics didn't provide troops, if Russia was required to send troops to the Asian republics to maintain order, that further diminishes the strength the Red Army has in the field.
The important thing is that each event in the chain of events after the POD must be evaluated in a different light.