Oh yes that is flipping horrible, sends shivers down the spine. I'm not a censor so please excuse my ignorance here but I feel that book retailers, high street shops and online, could get together informally, agree take a moral stand and not sell that sort of thing. Actually a friend of my eldest is a book seller, I will suggest that to her (know her well, she visited and stayed here quite a few times before marrying).
Such books are part of an era, they need to be kept and displayed occasionally such as at a exhibition in a museum.
If people are keen of buying one for themselves there will be ways and means on the internet, it won't be illegal.
It's mentioned here:-
https://www.jewishvirtuallibrary.org/propaganda-and-children-during-the-hitler-years