> what if the collection consisted of the following?

As the only books in it? Then it'd be best marketed as the "white supremacist conspiracy theorist starter kit". Throw in Mein Kampf while you're at it.

Just because a book is controversial doesn't make it good. No books should be banned, ever. But some books don't need promoting in a curated collection, either. They're useful for people doing literature research and understanding certain subcultures, but unlike the first list, they're not something useful and interesting to promote to a mass market, which makes them not good choices for a project like this.

Books are comparatively tiny, as data goes. If you have the space for a comprehensive list of every book in the public domain, by all means include those in it. But if you're making a curated list of a handful of books, and it's that list? That's certainly a choice.

See also this comment: https://news.ycombinator.com/item?id=48549512