After Louis XVI was stripped of his kingship, his official name (as a citizen of revolutionary France) becomes Louis Capet. Wasn't his (royal) house the house of Bourbon? I understand that the Bourbons were descended from the Capets, but why give him the surname of his ancestors and not of his actual house? Thanks in advance for any help you can offer.
This was a way to desecrate the role of the King his status. French monarchs and their close family ( the children, siblings,...Etc ) did not have family names like others or like we have now. They would be called by " their house name " if you want ( Louis de Bourbon ) or by the fact they were prince ( Louis de France ). To be more simple it would be like if they were called by the name of their land.
Henri de Bourbon for example, the future Henri IV and ancestor of Louis XVI was king of Navarre yet most people called him Henri de Bourbon, once king of France he could have been called Henri de France ( even though you could not call the monarch that way ).
This way a royal and also aristocratic system of naming ( first name(s) + family name + name of land or +first name + land ) and within Revolutionary France they tried to take away what was very Ancien Regime and reminiscing of an aristocratic and royal system. Calling Louis XVI Louis de Bourbon would still be like acknowledging that Louis was in someway the lord of Bourbon, and of course they could not call Louis de France you understand why.
Louis Capet though was placing him at the same level than ( most ) people.
The reason ( though there could be others ) is part of desecrating the role of monarch.