There are several reasons I can think of why this might not have happened.
They didn't know this (we don't know what level of technical knowledge the people who did the actual deleting had).
They knew this but wanted to be caught (controlled opposition).
They didn't have time (its a much longer process to write over sectors than to just delete pointers)
They never thought it would come to this. This goes along well with (3). It takes a lot more effort (time) than a normal delete, especially across multiple machines. Think about how many there are in the US.
I guess it make a sort of sense when we remember how they recklessly Jerry rigged the steal in the first place out of necessity due to Americans actually liking the America First idea thus voting for it in much larger droves that they had ever imagined. These audits are to depths and scales much larger than they are used to....and....they forget they don't have sole control of information anymore.
I would think the bad guys would know this.
There are several reasons I can think of why this might not have happened.
I guess it make a sort of sense when we remember how they recklessly Jerry rigged the steal in the first place out of necessity due to Americans actually liking the America First idea thus voting for it in much larger droves that they had ever imagined. These audits are to depths and scales much larger than they are used to....and....they forget they don't have sole control of information anymore.