The parallelism exists in order to deal with the aside, not because it's necessary for every element in the list. But putting aside that debate, here's the thi

The parallelism exists in order to deal with the aside, not because it's necessary for every element in the list. But putting aside that debate, here's the thing. You can't fix "to my mother, Ayn Rand, and God" by removing the comma. It's still ambiguous, indeed nonsensical. You fix it by adding "to". That is, the serial comma is not what's creating ambiguity, it's the omission of a word. But the ambiguity in "To my parents, Ayn Rand and God" is fixed by adding a comma. That is, it's the missing comma that's the problem. This is typical of the examples I've seen.