This is not the place I want to start an argument about the justification of using (or not using) serial commas. The AP Stylebook says:
IN A SERIES: Use commas to separate elements in a series, but do not put a comma before the conjunction in a simple series: The flag is red, white and blue. He would nominate Tom, Dick or Harry.But then it says this:
Put a comma before the concluding conjunction in a series, however, if an integral element of the series requires a conjunction: I had orange juice, toast, and ham and eggs for breakfast.Yep, it's right there in the punctuation section of the stylebook under comma. It's AP, in a muted way, saying it is OK to sometimes use the serial comma.
It just goes to show that you should read a sentence before doing search-and-destroy editing.