Perhaps in most cases it's information that an access to information coordinator wants to protect, but that isn't necessarily personal.
You know the nature of the exclusions, including national security. For an official, isn't it more tempting to censor more rather than less? Unless it's a very sensitive file like the report on the human rights of Afghan prisoners, which rarely occurs, it seems to me that officials have to weigh matters quite a bit more in order to be sure of avoiding problems. However, if they side more with the public and are more inclined to provide it with the information, as the public is entitled, they may have problems.