Some great ideas so far! I have a concept for X-Sector also:
It was run by a government facility, but back then it was not called the Ministry of Joy. They wanted to basically make everybody their slaves. They took the more forceful approach when it came to Oblivion, Enterprise and Submission, which partly worked. However, they did not work completely, and they found that the 'correction' wore off very quickly. So, they decided to change their image, and became the Ministry of Joy, formulating a back story saying that they'd been around for a long time - this came with a new leader, Dr Kelman of course. They theorized that if people were happier, then they would most likely be corrected, so they took the 'Smile always' approach. They tested out The Sanctuary which became their first 'joy' experiment, and seemed to work well. However, it seemed too slow for them, as not enough people were corrected at once - and this is where The Smiler comes in! This device carries more people at once, and their experiments were put to practice on the Marmaliser structure, which aired statistics and propaganda of why people should 'smile always'.
So in a nutshell, the Ministry did create Oblivion and co, but they got their name from the Smiler and the Sanctuary.
Prepare to be mermalized!