That depends on whether every startup CEO is considered a public figure by default. Does this guy have much name recognition outside of his niche? I would wager not.

Even if he is found to be a public figure, I believe the "actual malice" standard would be determined by the defendant's knowledge and regard/disregard for the truth at the time of writing -- meaning it doesn't matter whether the CEO later believed the defamatory statements were made in good faith.