How do I enable SEANDROID ENFORCING over adb inside TWRP?
I believe that what that warning is referring too is the SEAndroid ENFORCING, you can change that with setenforce

$ setenforce Enforcing
$ sestatus
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
Current mode:                   enforcing
Mode from config file:          enforcing
Policy version:                 26
Policy from config file:        sepolicy


You can also test this with getenforce

$ getenforce 
Enforcing