What amount of wood defects is acceptable in a lumber delivery?
That is some sub-quality lumber and I'd be very upset as well. It's almost like they dumped their reject pile on you knowing that you might not bulk due to the large delivery fees involved and the trouble you would have to personally return it.

They need to either replace it or accept a return including the delivery fee. I don't know that you really need some document to point at to be able to definitively say that it is not acceptable as any reasonable person would look it and know that it's unacceptable quality.

If they won't address it then I would use what is usable, don't use want isn't usable, set it out for them to pick up, let them know, and if they don't credit it then call your credit card company or bank and refuse/back charge the payment for that portion of the bad lumber