That's been discussed previously in https://news.ycombinator.com/item?id=33945628 and dang said in the topmost comment: "They're already banned—HN has never allowed bots or generated comments. If we have to, we'll add that explicitly to https://news.ycombinator.com/newsguidelines.html, but I'd say it already follows from the rules that are in there. We don't want canned responses from humans either! ...". There more to his comment if you're interested.

The HN guidelines haven't yet been updated but perhaps if enough people send an email to the moderators, they'll do it.