How long to crate a dog?

https://www.peta.org/about-peta/why-peta/crating-dogs/

Article in The Guardian.

One woman, Nina Torres, reckons it's fine for most adult dogs to be in a crate “nine hours maximum” during the day (with a walk in the middle), and then eight hours at night.

I cannot believe anyone would condone incarcerating a dog for most of the 24 hours of its life!! I'm with PETA!