Not true. You can also make your code fast enough so your server doesn't get overloaded by three requests per second. Then you can just handle the requests.
The disruption, manipulation, and most of all erosion of trust which bad-faith actors create (AI or otherwise) are the most serious issues in my experience. The concept of "evaporative cooling", in which a platform starting to go bad sees an accelerated departure of well-intentioned, high-value participants.
See the original article from 2010: <https://web.archive.org/web/20101012105003/https://blog.bumb...> (HN discussion: <https://news.ycombinator.com/item?id=1777665>).
And an interesting follow-up, 2015: <https://blogs.cornell.edu/info2040/2015/10/14/the-evaporativ...> (HN discussion, from 2025: <https://news.ycombinator.com/item?id=42597962>).
Also, uh, how does speeding it up that help with the AI spam? (Sorry, I should have emphasized that part of my most more, since that's mostly the topic of this sub-thread I was replying to.)