Joomla “is an award-winning Content Management System (CMS) that will help you build websites and other powerful online applications.”
Whereas object oriented programming is a style of programming.
The link, I would have to guess is this: “the object oriented attitude towards having a lego-like building set of an CMS” http://forum.joomla.org/index.php/topic,…
Even though Joomla isn’t a object oriented programming language, it is based on object orientation. You can enable parts, disable parts, have add-on, etc.
Hope this helps you.