The Soviets and communists in power at the time had very little regard for anything of historical importance and certainly saw no need for archaeologists. Destruction was common, as was repurposing; all done intentionally, IMO, to erase the culture. I walked through the Castle Hluboka in the Czech Republic, where they had housed cows inside the castle, on top of an extraordinary, centuries-old parquet floor consisting of 14 different types of wood farmed from off the property. It was amazing that any of that floor had survived.
Probably one of the reasons that the Slovaks were so anxious to break away after the Communists lost power.