When things don't make sense, often it is because information is missing and/or misdirection is in play.

For example -

This could be a cover for an operation that Internet Archive is not aware of, that is possibly tied to the Internet Archive truck theft (and recovery) that happened a few months back.

The truck's contents (drives, network gear, h/w's firmware, etc) was the way to get a payload into the internal network. And the DDoS attack is now covering whatever is really happening with lots of noise.

This is pure speculation on my part, but is much more reasonable than the pretense that someone would be stupid enough to DDoS the Way Back Machine because a few sites it auto-archived had some links to terrorists. In combination with someone also being stupid enough to steal a flaming truck (https://blog.archive.org/2016/04/20/truck-and-back-again-the...).