I think you are missing the point they were trying to make.

If NASA was having visible issues and difficulty in trying to get something like Hubble working in space, then perhaps the US’s spy agencies (known or not) also had the same difficulties. NASA employees wouldn’t need to have known about the NRO to help provide cover for their capabilities. Just publicly showing their struggle - for transparency - would have been enough.

(If NASA had a clue about the NRO capabilities or not, I doubt they would have cared. They still got their space telescope!)