How is this related to pledge? Even if you hate everyone that works on OpenBSD, software not being allowed to make system calls it doesn't need to make is a go

How is this related to pledge? Even if you hate everyone that works on OpenBSD, software not being allowed to make system calls it doesn't need to make is a good security practice. And with a Linux implementation of it, you don't need to involve yourself with OpenBSD. Steal the good parts, basically.