[UncleMeat]

Are those sources or collectors pieces?

We've got a lot of old books purchased second hand because historians tend to like old books, but none of them are primary sources used for research. All of the primary sources are coming directly from archives or inter-library-loans.

[franga2000]

Fair enough, but if you're a historian wiring a book about Hitler, you'll probably want a copy of Mein Kampf that you can take home either way, even if you'll still refer to the archive to double-check direct citations. And if their only option are the archived version because no unaltered copies exist on the 2nd-hand market, that's a pretty high barrier to entry.

Yes, there are plenty of of options if you can't find a copy on eBay, especially these days, but nonetheless, there are plenty of legitimate reasons for historians and laypeople alike to want originals of old works.

[UncleMeat]

I would be pretty surprised if it becomes impossible for a historian using these six books as primary sources to get long-term access to the original material. This can be a little more difficult with family archives since family archives do tend to paper over the colorful stuff in their history, but if people are truly concerned here about family archives limiting access to unsavory parts of their history for historians (which I don't believe is the reason for this outrage) then there's centuries of other examples to complain about.