Because it's the right thing to do, that's why

Rico says he has no shame in editing the writings of others that he purloins for his blog, but there is one thing he insists on fixing, like it or not: serial commas.
What's a serial comma?
They're the ones separating a long list of items in a sentence, like "he bought a range of vegetables, including rutabagas, carrots, beets, and lima beans".
Why are they important, even though most writers fail to put the one after 'beets'?
Because, as Rico's friend Rani Cochran pointed out, back when they both worked for Apple, it matters, as in this book acknowledgement:

"She wished to thank her parents, Ayn Rand and God."

What a difference a little serial comma makes...