That means, "don't go digging into our past lapses."
FBI did not inform Freeh of Kindred Spirit for two years (unless we look at Freeh's denial as CYA). Even then, it did not pursue investigation of Chinese espionage so as to not offend PRC at the time Freeh was trying to establish legat in Beijing.
CIA and FBI have not been merely inept, but stunningly, breathtakingly inept--even criminally inept.
See also the lengthy Colleen Rowley letter in the Bill Gertz Breakdown appendix: mistakes were made, and for calling us on them, we will crush you.