It was the fact that during the pandemic they forwent the rule that 1 copy they owned could only be rented out to 1 person at a time. Any library operates by that principal for exactly this reason. Even digital copies, they can only lend out so many at a time. During the pandemic archive.org ignored this rule which was noble of them considering the circumstances, but now those consequences are coming back to bite them.

Personally I think I was dumb to risk the whole Internet Archive to offer that and hopefully they use this as a lesson to consult more with their lawyers going forward.