On the importance of the Oxford comma:

There's an excellent comment at the foot of page 121 of What the F: What Swearing Reveals about our Language, Our Brains, and ourselves by Benjamin K. Bergen when he comments that "Language science doesn't come down on one side or the other in debates about split infinitives or the Oxford comma (even though there's clearly a right answer)." His footnoted discussion concludes that "The only argument against the Oxford comma is laziness."

I normally follow Fowler's Modern English Usage, which I remembered as guiding to not use the Oxford comma. However, on checking the third edition, the guidance is different from the second edition, and the Oxford comma is recommended. It still reads wrongly to my eyes. Best guidance if there's confusion is to restructure the sentence if possible.