I can only speculate.
Many of the documents you mentioned, such as B‑GL manuals on tactics and military doctrine, are freely available online.
However, when members leave the Canadian Armed Forces and have made a solemn declaration concerning their obligations under the Security of Information Act, they also return any documents that may contain sensitive or secret information. They are required to confirm on the form that all information of this kind in their possession has been returned. Of course,we're not allowed to keep secret documents at home, and are only allowed to have access to such published documents in our working environment.