Why such thing

http://operationl2p.com/

exists for CS, but not for QuakeLive?

Basic guides for Duel (per map also), CA and CTF (including map tactics), etc.

It would help growing community by making Quake more accessible for newbies?

Something has been started on Steam:
http://steamcommunity.com/app/282440/guides/

Even infamous diabz made something really cool
http://steamcommunity.com/sharedfiles/filedetails/?id=317119070