I'm sorry, this is just an elaborate argument of obscurity-as-security. You're clinging to privacy as though it were security, in stark avoidance of Kerckhoffs's principle.
You can use Shannon's maxim instead if you're going to be deliberately obtuse. The point is true for any system intended to be secure, and a network is such a system, as is the security software such as the claimed NAT software.
Or do you really want to argue that Linux Netfilter/nftables or BSD pf being open source is a security problem?
