I'll just add that Data was previously built as a Vi plugin, but it was evil, so Doctor Soong disassembled it and shut it down. A lot of trouble could have been saved it Dr Soong had learned how to actually exit Vi.
The reason has been purged, intentionally forgotten. Vulcans train their entire lives to take on a dangerous task: once every 66 years, the very best of the best view the reason why Python is banned. Once viewed, the Vulcan confirms that it is indeed a just and necessary action to ban the ancient language.
After the task is complete, the Vulcan goes utterly, irretrievably insane and dies mere hours later.