Speculation means: the forming of a theory or conjecture without firm evidence.
It's just a fun theory, which I think is plausible. It's based on my personal view of how Sam Altman operates, i.e. very smart, very calculative, makes big gambles for the "greater purpose".
I believe the comment was edited. The original comment made a mention of “seeing a lot of speculation” (paraphrasing) that piqued my curiosity.
The source of the speculation could further enhance or remove the probability of this being true. For instance, a journalist who covers OpenAI vs. a random tweeter (now X’er?) with no direct connection. It’s a loose application of Bayesian reasoning - where knowing the likelihood of one event (occupation of speculator and their connection to AI) can significantly increase the probability of the other event (the speculation).