I looked to see if this behavior of being unable to list subviews had been reported, so I'll add my cli usage here.
No job listing using the expected input from the browser url:
$ java -jar jenkins-cli.jar -s http://jenkins.mydomain.com/ list-jobs MainView/view/SubView
No view or item group with the given name found
Attempting to list SubView, MainView/SubView, and several other contrived variations result in the same "No job listing.." Using the cli to list MainView returns a list of all the jobs contained in all the subviews, which was unexpected and isn't the list I'm trying to fetch, but I found it interesting.
If there is a way to list jobs in a subview using the jenkins cli, that would be great.