Most likely laziness on the plesk developers to figure out how to deal with SELinux. If you run with plesk and SELinux in enforcing mode, please report any problems you have in bugzilla, and we will fix them or work with plesk to fix their code.
i'm running SELinux on plesk 11.0.9 now even tho its not recommened
i still didnt have any micro updates to the panel. just worried how it would it behave when installing/updating the panel. hope it will not break the plesk panel.