The Oxford Style Guide has made a stand, drawn a line in the dirt, and called the comma out.
It no longer supports the use of the serial comma. The serial comma is also--rather presumptively if you ask me--called the Oxford comma.
The serial comma is the comma used after "and" thusly: The Oxford Style Guide has made a stand, drawn a line in the dirt, and called the comma out.
The OSG wants to do this: The Oxford Style Guide has made a stand, drawn a line in the dirt and called the comma out.
Okay. Oxford can do what it wants. Doesn't mean it's right. I've always felt the serial comma is best to use because it makes clear that you're listing three things. Otherwise, it could be like this:
They say a reason for the region’s hollowed-out faith is a pervasive theology that departs from traditional Biblical interpretation on issues such as the divinity of Jesus, the exclusivity of Christianity as a path to salvation and homosexuality.
In the example above, which is a real one as well as a fantastic one (source), the lack of the serial comma implies that Christianity is a path to salvation and homosexuality. Which it may very well be, although I don't think that's what the author meant.
I believe publishers of fiction (in the US, certainly) follow the Chicago Manual of Style, which says to use the serial comma. In journalism, the AP Style Guide is followed, which does not use the serial comma, to their great detriment as evidenced above.
But hey, don't take my word for it (although you totally should). See what Grammar Girl has to say-- she uses just as convincing an example, if rather slightly less amusing.
Bottom line-- the serial comma provides clarity. I'm not sure why you wouldn't want to be clear to your reader, but if you favor confusion, then hey.