The Grammar Wars Wage on

"When it comes to writing fiction, you don't owe your English teachers or grammar Nazis anything. If you need to crack the rules to keep the rhythm or poetry of a sentence, do it. As long as a reasonably intelligent reader can parse the sentence that's all that matters."

--Richard Kadrey on grammar

Grammar "nazis" have been touting this legal proceeding (this blogger claims that the "Grammar debate [is] Settled" in bold meme-like fashion) as proving that the Oxford comma is the only way to go. Not using the Oxford comma might lead to mistaking it for other uses of the comma. Here is the example Grammarly provides:

"I love my parents, Lady Gaga and Humpty Dumpty."

One writer may be trying to say he (or his character) loves those three people/groups. However, another writer might have been using the comma to define who his parents were: Lady Gaga and Humpty Dumpty. A reader could become confused. Some use this example to command the necessity and inflexibility of the Oxford comma rule.

[Sidebar: In the above law case, I don't see a second reading of the sentence that would make the legal sentence understood in more than one way. It claims a list of exemptions to follow, so why would a writer list a non-exemption? Nonetheless, pay the time and a half overtime unless they're salaried upper class. Overworking someone means workers have to spend more time recovering. If you don't understand this, you may be a robot which should distribute its wealth to working human beings.]

As Grammarly points out, their sentence could be rewritten with the comma after "Gaga":

"I love my parents, Lady Gaga and Humpty Dumpty."

Conversely, one could still omit the comma and rewrite it:

"I love Lady Gaga, Humpty Dumpty and my parents." 

Now there is no confusion. No one (no one reasonable) will think he is trying to define Lady Gaga as an amalgam of Humpty Dumpty and his parents. But you never know.

Some writers might want you to conflate both notions at the same time:

"My greatest influences are my parents, Lady Gaga and Humpty Dumpty."

Here a writer might want you to experience both sentences simultaneously and to explore those implications. However, the rest of the work--that is, the context--should suggest this as well.

Note in the above Kadrey quote, he omits a comma in the last sentence, separating the dependent clause from the independent clause. Now, were I proofreading, I'd probably place it there in case he missed it. In some sentences it might confuse readers. Here it does not. I missed it on the first read.

Some writers remove commas (or pauses) for a reason--probably to speed up the passage, even if technically there should be one there. Whether you can get away with it probably depends on 1) if the sentence can makes sense without it, 2) how famous you are, and/or 3) how much of a grammar nazi your editor is.