All the labs astroturf all the social media, HN is not unique and OpenAI wouldn't be the only ones. I even receive offers sometimes on my email put in my HN profile, asking me to post about their project in exchange for money.
Be skeptical of anything you read online, not just what you think is "obvious astroturf".
Wait what? Why don't I get emails like this too? /s
(on a serious note, do you feel comfortable naming and shaming such companies, this is sort of a serious accusation imo and if not then how much money they are trying to give. It would be an interesting discussion and feel free to mail me if its confidential, waiting for your response and have a nice day :-D)
Wait so you're countering an accusation of astroturfing with an actual confession? That's new.