The FBI did not do a great job investigating Chinese espionage at the nation's weapons labs, either. But I think the bureau remains a highly professional organization that handles most of the investigations its conducts competently and professionally. Has anyone given thought to the fact that in any major investigation, the chief of police, FBI Dir, etc., makes the announcement with the officers working the case standing behind him. No one forced him to go on Meet the Press. FBI agents who worked on the case haven't commented publicly because FBI agents don't comment publicly on pending criminal investigations, and shouldn't.
Counterintelligence is extremely important.
So is the American presumption of innocence. The Agency was designed to serve the Executive Branch. The lack of plausible deniability has led to lack of credibility and wildly proclaimed errors to the exclusion of monumental routine success. In my opinion, the agency still maintains that secrecy. Despite past arms reduction treaties, the U.S. military is still armed with nuclear weapons enough to destroy the whole world dozens of times over.