1- It is revolution and in a revolution chaos raises, when chaos raises it is absolutely possible cars or furniture or even people burn.
2- The Ayatollah (Ruhollah Khomeini) and his followers did not believe furniture to be evil, but they believed luxury furniture was the symbol of aristocratic life (Persian: Zendegi-e Taghoti زندگی طاغوتی). However, This doctrine did not last much longer and vanished by passing time.
3- There was not any Fatva which issued on evilness of furniture.
4- Revolutionaries aimed banks and cinemas frequently and burnt their furniture. because banks considered as symbol of capitalism and cinemas as symbol of lechery and hegemony of western culture.
5- Conclusion: Burning/disposing of furniture was a common act during the Iranian Revolution, because in chaos of a revolution it is absolutely possible that people rush to some houses or banks or shops or... and burn the furniture of them. From beginning of Islamic Republic of Iran until now there have been a lot of Hezbollahis who used best furniture what remained from Shah's time or they bought them from west. For example, you can see the photos of banquets of presidents of Iran for foreign guests in Sa'dabad Palace.