> Under UK law, theft is defined in the Theft Act 1968. Go and read it. You will find that you are simply wrong.
OK, I've read it, and I still disagree. Some excerpts:
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A person is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it
Any assumption by a person of the rights of an owner amounts to an appropriation,
“Property” includes money and all other property, real or personal, including things in action and other intangible property.
Property shall be regarded as belonging to any person having possession or control of it, or having in it any proprietary right or interest
A person appropriating property belonging to another without meaning the other permanently to lose the thing itself is nevertheless to be regarded as having the intention of permanently depriving the other of it if his intention is to treat the thing as his own to dispose of regardless of the other’s rights
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It is clear that usurping someones right to make copies of their work, with the intention of treating such a copy as if it were your own, amounts to theft.