He had evidence that Lynch and Cinton were working to obstruct and bury the investigation. Lynch would not allow a grand jury be formed to give Comey full investigative powers and and she was providing sweetheart immunity deals with targets to both impede the investigations and prevent prosecution.
If Comey would have submitted the results to Lynch, she would have formed a grand jury, sandbagged the investigation and then wrapped the information up via grand jury secrecy so the American people would never know what happened.
Instead, Comey went public with the information to protect himself and the FBI because if he allowed Lynch to execute her cover up operation FBI agents would have went public.
Comey did the best he could under the circumstances, if for no other reason to protect himself in case Trump was elected and the case was revisited.
Most of his efforts since then seem to have been intended to cover his liability in the unfolding FISA unmasking scandals.
No, you are right he was in a bad position but he always makes the wrong decision. He should have told the AG to appoint a special prosecutor. He shouldn’t have gone public unless he quit. He should have bit the bullet and done his job, not make up new rules for James Comey.