I think if the IA had contacted authors and said, "Hey, would you be willing to make your book available for lending as part of our national emergency program?"

I think if the IA had contacted authors and said, "Hey, would you be willing to make your book available for lending as part of our national emergency program?" the average author would have been willing to opt in. But IA did not do that. Instead, it decided for itself that the authors should waive their intellectual property rights. I'll admit, there are some factors that make this complex. For one, many authors have book deals with traditional publishers, who would also need to be a party to the agreement, and they have different interests than individual authors do. For another, an opt-in program is currently infeasible, particularly for books that are older and out of print. That doesn't automatically mean, though, that an opt-out program is OK. Instead, it likely means that in the absence of a way to get authors' permission beforehand, there is no legal, ethical way to pull off what IA has tried to pull off. But my point is that you're comparing the programming community's voluntary "donation" of open-source software to an involuntary "donation" on the part of authors. When you take something that belongs to me without asking me, then even if I would have been willing to donate it had I been asked, you've still stolen something from me.