You have to think in the perspective of the the russian volleyball federation.
Because of the CEV league rank points and the nature of hosting the final round of Champions League. Some nations are able to manipulate the rankings.
If Russia just let Dinamo Moscow be eliminated before the playoff 6. It could affect the league ranking in the following years if russian clubs are unable to become successful anymore.
So the solution is not to let Dinamo Kazan host but to help the endangered club first. In that way... both clubs technically made it past the group stage which is infinitely better than only one club making it to the final round.
That's okay, all I'm saying is the quality of the F4 will be lower