You say CyanogenMod "bastardizes" AOSP, but it is really fairly close to AOSP. There are some added options to allow users to customize their device but they keep it down to a reasonable and usable amount. Beyond this, the primary changes to AOSP are for compatibility of the 100+ devices that CyanogenMod supports. CyanogenMod supports almost every major SoC architecture in one code base and it honestly does it very well, this is something that neither Google or the major OEMs do.
It is great that you build AOSP for your devices but don't act like CyanogenMod and others do nothing of value for the community.
Back to what was originally brought up about CyanogenMod, I don't think Samsung is releasing more source code *just* because of CyanogenMod or other 3rd party distributions of Android. That said, I do think Samsung at least cares about that community to some degree because they made this announcement at a small Android enthusiast conference made up largely of AOSP hackers. In addition, Samsung has also been making a concerted effort to reach out to AOSP hackers through forums and other means. At the end of the day Samsung is really just getting up to the standard of what TI and Qualcomm do with OMAPZoom and Code Aurora respectively.