I think it's important to explain what exactly a "RAW" image is before I go further into the reasoning of why I don't give them out, so here it goes!
A raw image is one out of thousands of other raw images from a session. These images compose of bad angles, unflattering poses, facial out-takes, funny expressions, out of focus captures followed by an insane amount of near duplicates -- out of those, there are amazing images with just the right attributes that need to be hand picked.
After a session is complete, I go over each and every one of these raw images until I find those images that have all the right attributes of a great photograph --- the right angle, the right light, the right expression and the right pose are key characteristics of a photo that will pass my meticulous curation process. This process is repeated a number of times as the pile of raw images shrinks until I have the very best images from the shoot that I can now work with as I start re-touching them into the final product.
So in other words, the majority of raw images are the unintended but absolutely necessary consequence of a photo shoot -- and just like with the thousands of screenplays penned every month, only a handful of those make it to production and become movies on the big screen. The rest never see the light of day, and for good reason! This same principle applies to raw and un-edited photos as giving out raw images would ultimately display my unfinished work, and like with any form of artistic expression I only want to make available my very best work.