The NSA, the original primary developer of SELinux, released the first version to the open source development community under the GNU GPL on December 22, 2000.[6] The software was merged into the mainline Linux kernel 2.6.0-test3, released on 8 August 2003. Other significant contributors include Red Hat, Network Associates, Secure Computing Corporation, Tresys Technology, and Trusted Computer Solutions.
Not to be an NSA shill because we should always be suspicious of alphabet soup agencies involving themselves in our software, but is there much evidence of anything suspect going on in SELinux?
The NSA is dodgy as hell but sometimes they push for things that are mutually beneficial for themselves and end users, like encouraging Rust adoption to reduce memory errors that create security vulnerabilities for US businesses, govt assets etc. SELinux fits into this paradigm because it also hardens server Linux systems that are used by most American online businesses and internal government stuff (I bet also including their massive state surveillance programs).