The Senate passed a rule to protect them from their dirty and public exposure.
Any complaint filed against a sitting senator cannot be opened for 50 years.
The rules ensure that, unless the Senate acts to release the information, any documents from Reade’s 1993 employment will not be made public until at least 2043.
https://www.breitbart.com/politics/2020/05/01/national-archives-admin-refutes-joe-biden-tara-reades-alleged-complaint-wouldnt-go-to-our-records/