Why do people watch police procedural shows?

I will admit to watching Castle, because of the Captain.

But why are CSI, NCIS, and even the Dateline show, so popular? Do people enjoy them because they show good triumph over evil? Is it some kind of competence porn, comforting folks into thinking that there are smart people bringing justice? These are the most popular shows on TV continually and I just don’t get it. Murder, people solve murder. What do you like about them, if you like them?