At the time that it was published, it would've been public domain by 1995 (so its creators might reasonably be alive at expiration). Anyone would be able to legally reprint it. Was that immoral? Or was it immoral to monopolize culture for another 1-2 generations?

It was a bad policy (immoral? your words) to "grandfather" everything in when the new law was passed. But I understand that wad the entire point (Disney) of that law.