Er, but the "stupidity" being hypothesized in this case is not John Gilmore's but rather the kernel maintainer he thinks was showing "malice."
There are tons of people out there, yes, even kernel maintainers, who are technically skilled and smart but for whatever reasons, prove to be bad at tasks like this and make bad decisions. It's usually not a conspiracy, and John Gilmore's vague handwaving isn't a very convincing demonstration that it was in this case either... :]
Every once in a while, someone not an NSA employee, but who had longstanding ties to NSA, would make a suggestion that reduced privacy or security, but which seemed to make sense when viewed by people who didn't know much about crypto. For example, using the same IV (initialization vector) throughout a session, rather than making a new one for each packet. Or, retaining a way to for this encryption protocol to specify that no encryption is to be applied.
There are tons of people out there, yes, even kernel maintainers, who are technically skilled and smart but for whatever reasons, prove to be bad at tasks like this and make bad decisions. It's usually not a conspiracy, and John Gilmore's vague handwaving isn't a very convincing demonstration that it was in this case either... :]