If this comment made sense to someone else who could rephrase it for me, I'd be grateful.

I think he means 'if nsa were logical actors, they would patch vulnerabilities, not leave them to be exploited by anyone, and they would use NSLs/collaborators/special NSA Voodoo to get their data'.

This idea is built on the assumption that (1) they think their defensive role is as vital as their offensive one, (2) there is plenty of special NSA voodoo to go round. Which is false. In particular, it is better that a hack come from a vendor vuln that anybody could find than from crypto wizardry (e.g. Logjam or signed drivers with md5 collisions).

The NSA did an illogical thing, therefore everything they do is illogical. It is illogical to create a backdoor that requires already owning the machine, therefore the NSA did exactly that.

This is also the biggest fallacy in economic, and even political theory. The assumption of rational actors.