> You can make a strong argument that under US law, works
> created by computers are not copyrightable.
I'm genuinely not sure what "works created by computers" means.
I don't know exactly how Jukedeck works, but it seems self evident that it is the product of a huge number of creative decisions - which sound samples to include or generate, which sounds can be combined in a pleasing way, which melodic patterns are appropriate for various genres, how melodic patterns are modulated over time, etc. etc.
It's not as if the Jukedeck team created a general purpose AI and said "go make some music". They designed a system that can generate a limited (though large) range of music based on their own sense of creativity, taste and style. I argue that the music generated by such a system is clearly creative expression and thus subject to copyright to the same degree as traditional creative expression.
I do not think "sweat of the brow" decisions are relevant here. The lack of "sweat of the brow" copyright means that simply performing labor without a creative element does not qualify the product of that labor for copyright protection. There must be a creative spark present in the generation or transformation of the work.
The fact that, with Jukedeck, the creative spark happens at the time of producing and editing the code rather than at the time of the code generating the music is not relevant in my opinion.