you're totally right about not being theft, but we have a term. you used it yourself, "distributed denial of service". that's all it is. these crawlers should be kicked off the internet for abuse. people should contact the isp of origin.
Secondly, denial-of-service implies intentionality and malice that I don't think is present from AI scrapers. They cause huge problems, but only as a negligent byproduct of other goals. I think that the tragedy of the commons framing is more accurate.
EDIT: my first point was arguably incorrect because some scrapers do use decentralized infrastructure and my second point was clearly incorrect because "denial-of-service" describes the effect, not the intention. I retract both points and apologize.
boo. took all the fun out of it ;)