The CEO is surely coming off as a crazy guy but the author isn’t a white knight or good Samaritan either.
The company closed the database access and the guy says “now I will disclose it or you can do X” Would he have not disclosed it if they offered hush money? We won’t know, for his case I hope not. In any case - what was he expecting?
I’d imagine there is 50%+ chance that any smaller company without a dedicated security team will take this disclosure as a threat and blackmail. Especially that on the first second and third thought it seems the disclosure would be a way for the author to boost their blog and content marketing for their consulting.
If there was a bug bounty or something on their site it would have been different.