It's more to keep the cables from everyone else. They were intended as context-sensitive commentary from diplomats to the US. They were not intended for general release, and as such, contain information and observations that were intended to give the US an advantage over their counterparts at a later time.
That is why they're "secret". They're not supposed to be viewed by any other country. If they are freely available to citizens, there is nothing stopping them from being freely available to everyone.
This is the shell game that has been played by all diplomats since the beginning of time. There wasn't really anything all that interesting about the cables, and all it really gave was a good look at how our diplomatic services work.
That is why they're "secret". They're not supposed to be viewed by any other country. If they are freely available to citizens, there is nothing stopping them from being freely available to everyone.
This is the shell game that has been played by all diplomats since the beginning of time. There wasn't really anything all that interesting about the cables, and all it really gave was a good look at how our diplomatic services work.