Like always with non-trivial question the answer is "it depends".
Some people in CompSci tends to think in overly strict principal lines, wanting the grey to go away. Perhaps this has something to do with how a computer works, in binary. But it's not how law works.
If one sentence contains insufficient creativity and/or artistic skill to be worthy of copyright, it does -not- follow that 50 similarily well-written sentences as a whole *also* does not deserve copyright.
In practice, merely doing more of the same, can give copyright. The creativity and/or artistic skill which is there adds up, and at some point crosses the threshold. This message as a whole, for example, may well be sufficient - whereas any individual sentence in it, would likely not be. (and I'm sure many of the sentences have been used in a very similar form before by others)
What I'm saying is, you *cannot* generalise from trivial examples to the whole tree. It's certainly possible that each of the examples, in isolation, is unprotected, while the sum total is protected.