Oh, for goodness sake. Can't you guys read.
The article says quite clearly:
...the author of an "unauthorized sequel" to Catcher in the Rye had settled the lawsuit brought by the estate of JD Salinger ...
It's not a ban. It's not a law. It's not a decision handed down by a court. It's a
settlement, an agreement, a deal. In other words, the author
voluntarily agreed not to sell the book in the US, in return for some benefit granted by the estate (such as them agreeing to drop their legal action).
To entitle this thread "Another book banned in the US" is just codswallop.