> SELinux's UX was significantly improved many years later

in what way?

Most of what people see as "SELinux" is actually the default policy, which started out as way too strict. Then SELinux-enabled distros such as Red Hat moved to a policy that only applies to system services, and leaves user-launched binaries as if SELinux was disabled.

And even for system services, you can disable SELinux for one service (permissive mode) and leave it enabled for the rest.

This has been the case for more than 10 years, but the damage was done. It's now very hard for users even considering learning the basics (which are not hard).