Pip search pretty much broken globally (reddit.com)

everyone's trying to get into machine learning baby

In my experience this suggests one or a few bad actors. They aren't necessarily malicious, just ignorant or negligent. Something like a one-off script someone wrote to scrape the endpoint, and said script escaped into the wild, perhaps through a blog post, and was copied by others. One or more of those ended up deploying the script somewhere with the capacity to generate a lot of requests repeatedly, perhaps as a cron job.