SELinux training "retired"?

I just started looking for some training in SELinux. I find some pointers to Red Hat training and certification, but the most significant one is this: https://www.redhat.com/en/services/training/ex429-retired-red-hat-certificate-expertise-selinux-policy-administration-exam

So Red Hat has retired its SELinux certification and the associated training, apparently. Does anyone know why, and where do I go instead? It seems like there is a serious lack of SELinux training available. I Google and find basically nothing. A couple years ago there would have been hundreds of hits. What's going on? Has SELinux become so integral to Linux in general that a separate course is no longer needed? Judging from the questions in this forum I would guess not. Has SELinux fallen by the wayside and is soon to disappear? I doubt that even more.

Anyway, where and how is SELinux training available. Any suggestions greatfully accepted.