My guess for the closure of airspace is that they are moving troops and attacking towns. Their aircraft certainly don't have ADS-B (or others) operational and may be at any altitude and may not have lights. I recall my nephew telling me of this problem when he was a bush pilot for the UN 20 years ago. Aircraft that no one knows about doing things they don't want anyone to know about. Whilst commercial aircraft are at altitude, if they make an unscheduled descent for a pressure problem - having them bump into an undocumented craft carrying guns or mercenaries is not a good look.