What I mean: I’m wondering if people let their bots post/comment on their behalf and how we can detect and prevent this from happening.
I don’t think simple things account creation date alone is a reliable qualifier. You could easily give your bot access to post using an old account.
But overall - whatever dang & co are doing to minimize the problem seems to be working fine.
What's old is now 'new' again.
As the other comments say, there is a lot of spam that is detected automatically and manually. You can take a look at https://news.ycombinator.com/newest with "showdead" enabled. While you are there, remember to upvote good post and flag spam.