I think a lot of commenters are missing a crucial piece of information about this. These books are being removed from publishing by the owner of the IP, don't blame ebay for this.
I would argue that this isn't really censorship, although it is muddied by the original author being dead, and this being a company set up to manage his IP by his wife.
(I would also argue that ebay removing them in general isn't something to scream about, private companies should be allowed to curate their systems however they want. But that's a different argument)
Ceasing to publish new copies is different than disallowing the exchange of existing copies. The owner of the IP chose to do the former, eBay chose to do the latter.
I would argue that this isn't really censorship, although it is muddied by the original author being dead, and this being a company set up to manage his IP by his wife.
(I would also argue that ebay removing them in general isn't something to scream about, private companies should be allowed to curate their systems however they want. But that's a different argument)