It is subjective of course. I still don't think an entire plot should be written in short hand English etc, if people are using it for creative purposes in a portion of a written piece then okay. I see nothing wrong with them using a umm "University standard" or "High School Standard" in the section. It's also to prevent people from doing this and calling it their creative writing:
gegergaergergergaergergaegergaegaw jkwhnkrjgnwlGAEKLRANEB,FMB
GJSKNTGJAWN D,GSNE RNRKLR JSEKGN D,JN SZ,F
ZNBRGJZNREJGNWAELKGFANWMRK,FNE,N,M DFNZSJkjesr jen
erkjgnerjgn dd jenfj,nf,fn,ef awernw4rjli4 jn ,fjntgjaeogljalwgjaeerkjg
fin.
Anyway, it's not as strict as you think it is. It's just there to cover their asses when they need to trash a completely ridiculous thread. I am sure if you went in there and wrote something legit and it had a bit if slang they'd leave it be.
At the end of the day I am unsure why this matters so much to you, are you planning on writing an entire piece in slang? If you are then send a PM to Brightshade and work something out. It's really as simple as that.