Materials covered by the pontifical secret include diplomatic communications made between the Vatican’s nunciatures around the world, but also apply to a range of other subjects. These include private dossiers and recommendations on priests and bishops being considered for promotion. Controversially, the secret also covers penal processes concerning major crimes handled by the Congregation for the Doctrine of the Faith, including cases involving the sɛҳuąƖ abuse of minors.
The reasons why the secret is applied to different materials depend upon the circuмstances. Private communications between what are effectively papal embassies and the Vatican’s Secretariat of State are protected by confidentiality in the same way, and for the same reasons, that other diplomatic correspondence is kept classified. Files pertaining to bishops or prospective bishops are handled in much the same manner as confidential personnel matters are treated in companies or other institutions.
In judicial cases, the secret is meant to protect the privacy of victims, the good name of the accused (at least until they are convicted), and even the confidentiality of the accusers, who might be under the authority of someone under investigation.

https://www.catholicnewsagency.com/news/what-is-the-pontifical-secret-78234

Wouldn't it be grand if those in power protected not only this secrecy of confidentiality but also protected the Deposit of Faith, Catechism,  the True Mass and Sacraments?

The Novus Ordo keeps secrets, that's for sure.
As for the Catholic faith and the Sacred Traditions, there aren't for sale because the Novus Ordo has already taken them to the trash and posted guards on the trash to make sure no Catholic soul tries to retrieve them.