Nobody can give credit to a single CMS.
Yes it also depends on how well you use them, and how well you are used to that. Any CMS like Joomla, Drupal, WP is highly customizable and any of them could very well suit your needs.
So, there cant be any single CMS to be given all the credit.
Wordpress is easier to understand, whereas Joomla is somewhat tougher to master at. Drupal lies in between these two Platforms. All the three have their own security measures, and all are secure for any content.