It is a matter of fact in that either there were zero missions of such a nature, or there were one or more. I.e., you can refute it by identifying even just one such mission. Posting a list of random DoD missions is not a substitute for that.
People employed at NASA for decades, in a position to know and report even facts not published, that they have had no reason to lie about, say it is true. No one has come forward to say not.
That’s my point. Note I said it was unverifiable. Only one of us is pretending it’s a verifiable fact. I also know manny people who work at NASA, going back from the 1970s to present day. Some were astronauts. Many worked on the shuttle program directly. We seem to have very different ideas about what constitutes a “fact”.
But again, none of that matters unless you can verify your claim. We can just leave it as a known unknown and stop pretending it’s anything different.
The issue I'm pointing to is the veracity of your claim that they did not. You stated it with certitude that, by the very nature of it being classified, you likely do not have. So either you're out over your skis regarding your certainty or the person you talked to willfully disclosed classified information.
It's no different than if somebody on here said with certainty that there was a second gunman on the grassy knoll. Because, you know, they have a source at the CIA who said so. But we can't verify it because they classified the information. But trust them. They know a guy.
Of course in both cases there is truth that supersedes opinion. Whether or not anyone should believe one claim over another is a different story. Just because you say something with conviction doesn't make it true and just because you "know a guy" doesn't make it credible.
You may credulate it or not by whatever criteria you like.
The fact remains that STS was massively expensive, and unnecessarily, and it ate up budget that could have been used for much better things, and probably would have.
Skylab really did fall out of the sky. The US really was for years dependent upon Russia to launch its astronauts. We really did get only just the one Hubble.
People employed at NASA for decades, in a position to know and report even facts not published, that they have had no reason to lie about, say it is true. No one has come forward to say not.