Why does RHEL (and its derivatives) use such an old kernel? It uses 2.6.32-xxx, which seems old to me. How do they support newer hardware with that kernel? As far as I know these kind of distributions do run on fairly modern hardware.
Because Red Hat Enterprise Linux is foremost about stability, and is a long-lived distribution (some 10 years guaranteed). RHEL users don't want anything to change unless absolutely necessary. But note that the base version of the kernel is old, RHEL's kernel contains lots of backported stuff and bug fixes, so it isn't really old.