Because it's a tactical own-goal. Fair use as a defense looks at the market factors and the Emergency Library did damage the possibility of that defense while it was active; IA suddenly was giving out unrestricted copies of books they own. I can't do that with my digitally owned music without being seen as a pirate and fined for it - what makes IA different? Sure they have standing as a library in the eyes of the US government which gives them some defenses against the DMCA, but that still requires respecting the DMCA. The Emergency Library in that regard was no different from something like LibGen or the many other book piracy sites out there. It being temporary doesn't really change that.
That aside, to my understanding the failure of IAs version of CDL was established during fact finding but I think if the IA hadn't so blatantly just decided to disable all lending restrictions, the courts would probably have been willing to chalk it up to typical organisatorial negligence and left it at that.
It's just a very stupid move on the whole and frankly actively dangerous when you consider the other main service that IA operates (the Wayback Machine). The only defense the IA really has is "we're so essential to the modern internet that we shouldn't be punished for breaking the law", which I don't think the courts are gonna look very highly at.
And mind you that I say this as someone very sympathetic to wanting a more lenient look at modern copyright. It doesn't change that the IA decided to poke a dragon and got burned. There's better ways to advocate for change than to expect the courts to not follow the law because you want them to put in a new exemption for you.
If it was permanent then one library would buy one copy of each book and everyone would be able to borrow it forever, so no library would have to buy another copy of the same book.
If it's temporary then libraries will have had enough copies for the typical number of people who borrow them at any given time, even during the period when the emergency library was operating, and would continue to buy them because a book is a decades-long investment for a library and they would reasonably expect to continue to need the same number of new books going forward as they always did before.
Essentially the emergency library would cease to exist before it had a meaningful effect on the purchasing behavior of libraries. Being temporary makes all the difference in the world.
That aside, to my understanding the failure of IAs version of CDL was established during fact finding but I think if the IA hadn't so blatantly just decided to disable all lending restrictions, the courts would probably have been willing to chalk it up to typical organisatorial negligence and left it at that.
It's just a very stupid move on the whole and frankly actively dangerous when you consider the other main service that IA operates (the Wayback Machine). The only defense the IA really has is "we're so essential to the modern internet that we shouldn't be punished for breaking the law", which I don't think the courts are gonna look very highly at.
And mind you that I say this as someone very sympathetic to wanting a more lenient look at modern copyright. It doesn't change that the IA decided to poke a dragon and got burned. There's better ways to advocate for change than to expect the courts to not follow the law because you want them to put in a new exemption for you.