Not really. He can only speak of his personal experience, unless he's got documentation to back up the claim that this is actually NIST policy. Ketcham just did mathematical visualizations, not investigations.
It's somewhat besides the point, because NIST says there IS a "specific and compelling reason" not to - so the question is if Ketcham is qualified to judge the reason.
Thanks! Even just doing data visualizations, wouldn't his years at NIST give him direct and/or indirect knowledge of appropriate security practices for scientific data which must be kept secret? Doesn't his perspective add a little credence to complaints that the data are secret for reasons that are also secret? Isn't his opinion more valuable -- or at least uniquely different -- than others who have made the case for scientific transparency in the past?