The fact that Red Hat picked 2.6.32 as a base kernel to build on for EL 6 doesn't seem to part of any coordinated effort. It just happens to fall in the right timeline. In the case of EL6, we are talking about 7 to 10 years with increased divergence over a period of time considering the enterprise model of backporting fixes or in some cases rewriting or creating new patches because upstream has moved ahead in a different way.
The decision to maintain 2.6.32 series for a longer term is a independent one and while there is a small level of intersection between them at this point, that won't last. It is unfortunate, certainly that stable release process is not made easier now but the individual patches get pushed upstream anyway and the fixes end up in the Linus tree and the benefits shared.