RHEL running with SELinux enabled has been a thing since I worked at Red Hat 12 years ago, and Amazon Linux 2 was based on a CentOS upstream that had the capability of running in that way. All certification had to happen with SELinux enabled, and any distro provided service was setup to run with full restrictions, and it was the default on for all Professional Services work.

However it became a problem once you used 3rd party software as step 1 of most install guides was to disable SELinux.