Because we want
extreme customisability.....
There are many
open source cms available but - none of them supports the amount of customizability we require. Our aim here is to make a website which will be used only in the course event. But the cms available are built for web-site management. We don't want that. We want to host an event, that calls for rapid updates, browsing of online files, edited source code AND having a WYSIWYG editor at the same time, not to mention extensive support for features like quiz, report, user-management etc.
Of course if a cms is robust enough to be used in an event, it is definitely fit for hosting a website ;) ....