I meant hacker as in a computer operator using some ingenuity to overcome a problem. Since the use of app_config.xml requires knowledge of the BOINC system beyond its everyday use I consider it a basic hack.
I was using the word hacker as way of creating a distinction between users who are willing to take extra steps to optimize their systems and users who prefer automatically configured settings or GUI based configuration tools.
Some definitions of Hacker:
https://en.wikipedia.org/wiki/Hacker (definition 1)
http://www.catb.org/jargon/html/meaning-of-hack.html
https://en.oxforddictionaries.com/definition/hacker (definition 1.1)
I did not intend to imply malicious or unauthorized activity.