Can some explain why would a billionaire like Altman care about the opinions expressed on HN?
Given the political power they have, particularly now with the Trump administration, whatever "optics" exist on this forum seems completely insignificant
You forget how many influential tech professionals are present here (especially those in Silicon Valley) and that Altman was president of Y Combinator for several years.
Elon Musk seems to care a great deal about a lot of stuff that frankly isn't any of his concern, not really. Trump care immensely about shallow stuff that's really below what the president of the United States of America should spend time on.
Altman has some reason to worry, because developers and the users of HN are then ones he needs to promote/hype his products. OpenAI still needs customers and they need to sell tokens and a large number of users on HN are not only not buying, but are becoming increasingly hostile towards the product Altman is selling. My guess would be that he'd assume that the users on HN are in some sense his peers, and they are currently extremely divided in the question about the value and dangers of LLMs, and are increasingly critical of the business practises of OpenAI (and other AI companies).
That's what they want, but do not yet have.
It's easier to take over a resigned population. And stating "resistance is futile" is cheap and it might weaken opposition.