The problem isn’t the churches, but their priests.
Nearly all the Orthodox Churches in Ukraine adhere to the Ukrainian Church, only a small minority remain loyal to the Russian Church.
As for the rest, its war. The US also banned men from evading conscription in WW2.
There is still a large number of Russians that populate Ukraine, and have for many generations. And they are supposed to watch their churches being closed, and accept it? How do Catholics here feel about their local Churches being desanctified and turned over to muslims?