It's common in tech for employees to know things about software that are different from what the CEO says. It's his job to decide when and what to say, not the employee's. I'm surprised the guy didn't already know this.
This is a bit of clickbaity article, the tweet in question was comparing the unreleased model's performance in a negative light against competitors.
Also a number of other tech companies have similar policies in place for speaking about unreleased products
Pretty dumb hill to die on honestly. It's pretty standard for software companies to not want you to share any thoughts/intelligence on unreleased products. Even if they were maybe pissed you didn't say Grok3 was the best, that it exists is irrefutable and gives them grounds for firing for sharing company secrets (and not an opinion).
Yes - it's one thing to have posted it, another to decide it's a good reason to lose your job over it in a very public way. I suppose he's someone who is talented enough that a competitor won't care about this as a factor in a hiring decision? But even then, you'd think you could only do it so many times...
Eh. Posting your guess about how an unreleased product you're working on will stack against competitors in the market seems like a bad move.