Because a derivative work must "as a whole, represent an original work of authorship". https://www.law.cornell.edu/uscode/text/17/101 https://www.law.cornell.e

Because a derivative work must "as a whole, represent an original work of authorship". https://www.law.cornell.edu/uscode/text/17/101 https://www.law.cornell.edu/uscode/text/17/101 (Not a lawyer...)