Note the crucial difference between writing this as an enumerated list, and writing it as a continuous sentence.
In the former case (used here) the “xyz is not” distributes such that each point on the list can be read as a complete sentence, giving your (correct) interpretation.
What seems to confuse a lot of people is that if you write “xyz is not A, B, and C”, the “not” no longer distributes the same way, and (A, B, and C) is read as a single condition, giving the alternate (incorrect) interpretation.
Note the crucial difference between writing this as an enumerated list, and writing it as a continuous sentence.
In the former case (used here) the “xyz is not” distributes such that each point on the list can be read as a complete sentence, giving your (correct) interpretation.
What seems to confuse a lot of people is that if you write “xyz is not A, B, and C”, the “not” no longer distributes the same way, and (A, B, and C) is read as a single condition, giving the alternate (incorrect) interpretation.