"Proxy request refused" tells that it's the server having issues not ignoring case, it thinks you're trying to proxy to another domain. However it's good practice for clients to lowercase domains before making requests, just incase the server is badly made (like here ;)

As a method of configuration, agate allows people to put a .directory-listing-ok file in directories people want listed. https://github.com/mbrubeck/agate#directory-listing

Agate's decision to have it off by default, and to hide files beginning with a .dot, I think should be coped across for safety's sake.