File sharing is what you do with something you own.
No. File sharing is when you make files publicly available. Of course, you need to have permission to read in order to do that. Ownership however is not required.
Piracy is sharing files that you do not own.
No. Piracy is when you force the crew of a ship to hand over the control of a ship. For doing so, the pirate must possess the tools of coercion, arms. According to the United Nation, the piracy is a very serious, violent crime. I don't see any reference to file sharing in the text, do you? In any case, making the connection between the two is an act of exaggeration, association with one of the most violent behaviour, just like calling people who disagree with you, nazis or mass murderers.
Movies are about fiction (virtually always).
That may be true. However the mentioned fictional film is about the actual meaning of the word, piracy, not the fictional content that you just made up above.
Some educator uploading material they do not own is piracy. It may also be civil disobedience.
Again, no. I'm not aware from the story that the said teacher invaded private ships on the seas and forced the crew to hand over the load.
Some 12 year old downloading Katy Perry is piracy. It probably is not civil disobedience.
No, not even by your own definition. As long as the 12 year old takes the publicly available copy and only downloads it, there's no file sharing involved. It is only the case if she or he starts to make her own copy publicly available, being a leach or a seed in a torrent network, or the analogue in some other way. If someone leaves a Kate Perry CD on a bench in a box labelled free to take, and bring the CD for listening, would you still accuse her with hijacking ships, threaten ship crews with murder, and so on?
If the law says that file sharing you do not own is illegal, that is one thing. Using a label "pirate" for those who do so is an other, an act of magnifying of the act what they did. File sharing is not theft, not pirating. It is what it is: sharing files, sharing information. It may be debatable that the information sharing is a not a basic right, yet, it is not by default. One must sign non-disclosure agreements if one is expected to keep some information secret. This always happens before revealing the information. Consumers of digital media aren't restricted by two-side non-disclosure agreements before purchase. If the law is not consistent it can't be applied, and enforcement of laws which aren't consistent with the nature of acts it supposed to regulate can't be, by nature consistent either. Non-consistent law enforcement is the tell tale sign of an oppressive political system. In this case, the source of oppression is the political lobby of different publisher cartels. Civil disobedience is the right of the citizens in such a case, not an option.
You can apply the same idea here as for homosexual acts. For hundreds of years homosexual acts were illegal and inconsistent of the nature of sexual life. The justification was that homosexuality is a crime against nature. Of course, Nature as such, isn't a person, and is and was mostly linked to the idea of God, again, a non-person. But by citing God/Nature in the justification it exceeded the entire framework of the issue, and brought it in to a stage where it doesn't belong. Ditto with piracy and file sharing. This is a question about the way we handle information, and has nothing to do with piracy.