If the title of this post made perfect sense to you, then you’re way ahead of me. But just in case, we’d best recap. Neal Whitman wrote a good article at Grammar Girl recently on the possible origins of because as a standalone preposition. This helpful passage from Whitman sets out the context:
In Standard English, the word “because” can be used two ways. One of them is to introduce a clause, as in “Aardvark was late because he was waiting for the repairman to show up.” Used this way, “because” is a subordinating conjunction. The other is to team up with “of” to form what’s called a compound preposition. For example, “Aardvark was late because of heavy traffic.” In the past three or four years, though, a new usage for “because” has been developing.
The new usage – older than 3–4 years, mind – is what Laura Bailey and Mark Liberman, respectively, have referred to as “because+noun” and “because NOUN”. Liberman says the idiom usually seems to imply “that the referenced line of reasoning is weak”. Sometimes, yes, but it’s also commonly used just for convenience, or effect: No work tomorrow because holidays!; Of course evolution is true, because science.