There's nothing cynical about leaving a job after cliffing. If a company wants a longer commitment than a year before issuing equity, it can set a longer cliff. We're all adults here.
My criticism is that that's a detail that is being obscured and instead other explanations for leaving are being presented (cynically IMO).
There might be some marginal drama to scrape up here if the post was negative about OpenAI (I'd still be complaining about trying to whip up drama where there isn't any), but it's kind of glowing about them.