Their download service does not require authentication, and they are kind enough to be hesitant about blocking IPs (one IP could be half of a university campus, for example). So that leaves chasing around to find an individual culprit and hoping they'll be nice and fix it.
They could however rate-limit per IP with possibly a whitelist or higher limits for cooperative universities that are willing to prevent abuse from their own network. Unless they are facing a DDOS but then this appeal is even less likely to help.