BFGMiner is great, but saw recently it have some tweaks and improvements and code purposes still required, especially on Mac. It was impossible to make it work last week with scrypt & CPU/GPU on a OSX. LukeJr said coders are free to come and improve BFGMiner on Mac computers.
I'm not sure what you are referring to - do you have a link?
CPU mining is not enabled by default in bfgminer or cgminer (though either can be recompiled with it enabled). I just tried scrypt mining with bfgminer on my Mac and it worked fine. Check out the steps in this article:
http://blog.nwoolls.com/2013/05/02/litecoin-mining-on-mac-os-x-gpu-mining/