Oh, they just mean identity politics diversity. I was hoping they would diversify the range of topics past just literature, art, and philosophy. There are important books in the fields of math and science that have shaped society, but not included in the Western Canon. Euclid's Elements, On the Origin of Species, A Brief History of Time, etc.
I enjoy reading works by people who are different from me. I'm excited at the idea of reading the lost works of a great writer or thinker who had interesting things to say but was not widely published because of the politics at their time.
Is wanting to read that controversial now? Do I get the scarlet letters of SJW? All the examples you mention are Western and widely available.
When a publisher decides to publish Woody Allen because others wouldn't publish or market it, it's lauded on HN as defending freedom of speech. When a publisher decides to publish works by black people because in the past publishers wouldn't publish or market it, it's referred to as "identity politics diversity" on HN. That is my main point.
