Both of the examples you gave are people that died in the last 30 or so years. Their (published) work is still legally under copyright. 70 years after they die, by US law as far as I know it, it goes into public domain. That doesn’t mean people can’t still sell it but that’s why you see tons of old pre 1940s books badly reprinted and sold on amazon as cheap, in-demand paperbacks.
I’m not sure that faceting diagrams that haven’t been formally published in a book or magazine fall into protection at all. I doubt it, as there is no way to prove the date of authorship.
Lapidary journal is a different story. The company that put out the first 50 years of issues no longer exists and the magazine was purchased by a new company. I’m currently talking to them about sharing early issues that I have. Since they don’t have them and don’t seem to care about them I hope they will allow it.
That’s the law. Moral issue is a different thing and it’s obvious you and I don’t agree on it so there’s no point in discussing it. For me, as a historian and academic researcher, it’s essential that I am able to have unrestricted access to prior written works. I appreciate libraries and archive.org for making this so much easier but in the case where there are very limited copies of certain books or they only exist in inaccessible collections, what else is one supposed to do?
As a side note, considering all the other atrocities going on in the world, isn’t there a more constructive battle we should be putting our energies into?