Even though I almost posted a comment like yours earlier ("I'm an African-American lesbian with a seizure disorder, and ChatGPT is finally enabling me to finish my novel!"), I'm not sure how many of these comments are bots, since many are from quite old accounts, e.g., this one replying in a bot-like manner to a fairly obvious bot actually registered in 2014:
https://news.ycombinator.com/item?id=47286976But when you inspect Mr. "AI girlfriend's" post history, even ignoring the AI promotion, it's all superficial: short, unargumentative, inoffensive posts. I wouldn't be surprised if there's a black market for HN accounts similar to reddit accounts.