I have heard of that. I like the convenience of Kindle and e-books (and it took me a while to switch over from real books) but I am beginning to see the possible hazards.
I only use my Kindle to read PDF books from Archive.org. I'm currently rereading The Prince.
Amazon can not only delete your books. It knows and stores EVERYTHING you do on your Kindle. What you read. What you browse. What you search. What notes you make (if you have a Kindle Scribe).