Yes, we hear this every time. But this is the same project that advocated systrace, which provided access control with respect to syscalls. I do not see much of a difference between systrace and a mandatory access control framework, except that the implementation of systrace was flawed, it didn't support file labels, and SELinux has a more sophisticated policy language.

The OpenBSD Project has a very narrow view of security, and do little to improve attack mitigation for software that is not in the base system (ports).