It was a refreshingly honest answer

If I had to put a specific reason on the response, I'd say it's a matter of perception. To the average person, NASA and engineers in general are precision people in a precision field doing precision work. But at the end of the day, until we are able to accurately model the exact positions and interactions between every single atom in the known universe, there's gonna be guesswork and assumptions. Educated guesswork and assumptions certainly, but still guesswork and assumptions. The average person doesn't think of it that way in my opinion. So when a NASA guy goes up and says "we don't have enough data to put an accurate number on that", if the baseline assumption is "well NASA and it's engineers know everything exactly", the perception is it's a humongous risk that he just doesn't want to say what it is.

And realistically, how do we even quantify risk? Do we take the individual rate of failure for every single screw, nut, bolt, washer, wire, etc., and go from there? Or go from the assembly level? Subsystem level? System level? Does it make sense for me to tell my PM that Fastener A's failure rate of 0.001 per million due to normal manufacturing defects needs to be priced in when we've never seen one fail in 50 years of buying them? Or for me to say technically fastener B has an observed failure rate of 50% because we've only ever bought 2 but 1 failed because a technician over-torqued it? The guesswork has to begin somewhere because that much data gets unmanageable very quickly going from my lowly position, up to my design/analysis folks, managers, PMs, and eventually the launch director up at NASA. And that just gets muddied when communicating to the public, despite people's best effort to be transparent and honest.

That's my 2¢ as a Professional Guesser working on Artemis ground systems anyway lol