I feel your pain! I experienced one guy who was ‘like that’. Fortunately, he was not chair, treasurer or secretary, but he was there to save us from ourselves and explain in no uncertain term how and why we were completely incompetent or worse. He had bought a unit not long before joining the EC and as soon as he joined the EC he proceeded to explain how everything he saw about him was done incorrectly. He gave the impression of gravitas and competence but was not above making incorrect assertions of easily disproven ‘fact’. I think he was not accustomed to being disagreed with. He eventually resigned from the EC without explanation. There were multiple possible triggers. While he was there he was a constant source of stress for other EC members.
Do you have a managing agent? It could be good to talk to the agent. He/she might be just as frustrated by the secretary and might be pleased to see a change of personnel. However, the agent just has to work with and take direction from whoever is in place on the EC. The agent might agree to mail a letter to all owners. That would get around any reluctance to hand out the mailing list. What about the chair or treasurer? Do they get on with the secretary? Is it a case of nobody else wanting to do the work so the secretary does everything, however he feels it should be done?