Copyright law says that when you buy a book, you own it. You can give it away, you can lend it, you can pass it on to your descendants or donate it to the local homeless shelter. Owning books has been around for longer than publishing books has. Copyright law has alwaysrecognized your right to own your books. When copyright laws are made -- by elected officials, acting for the public good -- they always safeguard this right.
But ebook publishers don't respect copyright law, and they don't believe in your right to own property. Instead, they say that when you "buy" an ebook, you're really only licensing that book, and that copyright law is superseded by the thousands of farcical, abusive words in the license agreement you click through on the way to sealing the deal. (Of course, the button on their website says, "Buy this book" and they talk about "Ebook sales" at conferences -- no one says, "License this book for your Kindle" or "Total licenses of ebooks are up from 0.00001% of all publishing to 0.0001% of all publishing, a 100-fold increase!")