There are no claims that SELinux does anything other than secure the system, but if you're going to distrust things based solely on who sponsored them (Chinese government for this Linux distribution) then it makes sense to ask if this logic is applied consistently.
To make it crystal clear: I'm not saying SELinux is untrustworthy. I am just asking the poster if they would trust SELinux knowing that it came from the NSA. I ask the same question of people when they claim that Windows/OS X is untrustworthy because the NSA may have made changes to spy on the user through it.