SIP doesn't block /opt for the exact reason MacPorts relies on /opt: It's not part of the existing operating system. In other words, this situation isn't just g

SIP doesn't block /opt for the exact reason MacPorts relies on /opt: It's not part of the existing operating system. In other words, this situation isn't just good luck for MacPorts, it's a direct result of the design decisions behind MacPorts, and the design decisions behind homebrew.