Counter-take:

Linux is only secure because of OpenSSH.

In all seriousness, the OpenBSD guys are very conservative with technology. The OpenBSD pf stack (as well as much of the kernel) isn't heavily threaded due to the risk of race conditions. They also (correctly) predicted a lot of the speculative CPU attacks by not supporting it by default.

They've done a lot of security research and pioneered a lot of open source work around OS-level stack smashing technologies, like memory executable-space protection (W^X), early process privilege separation, memory space randomization, etc. Some of these features are not great for performance, but do help and have been adopted by other systems.

You're basically arguing that an armoured car sucks because a Ferrari can smoke it on a race track. There are times you want a Ferrari and there are times you want a Brinks truck.