I don't even know what to think about this one. I'm not angry, more confused than anything. There's only one mod there so i asked them, and they said "It's against policy. It's the abbreviations policy."
I see no such policy anywhere, so who knows what's going on. Is it only the NYT that can't be abbreviated? What about the US? Is LOL forbidden too? And if so, why are we forbidden from laughing there!
They didn't even remove the comment.
The mod is user qrstuv. Maybe the only abbreviation allowed is when they say one? That's a power trip!
Being a pedant is fun but you need to get your shit straight. Abbreviation is an umbrella term that includes shortening of words or phrases in various ways including acronyms and initialisms.
Unfortunately, you are likely wrong. "Abbreviation" — to my knowledge — is a borrow from French and simply means to shorten in time or length; nothing about words specifically, as you are suggesting.
It's worth noting that the OED is, in its nature, a descriptive dictionary; therefore, this rather general definition should be taken with a grain of salt. The word may — indeed, as it is common — have a more specific meaning, as you suggest.
Edit:
Nope, you were definitely wrong (this time a free dictionary!):