The issue is reproducible categorical evidence of what it actually is. You can't take those radar plots and say with 100% certainty that it was NHI when there is the equally remote possibility it was some form of atmospheric condition, or adverserial radar spoofing. Scientists need to reproduce that data to confirm how they were made, and in the end they are only trace evidence.
I must admit if I was KirkPatrick, I wouldn't have been anymore forthcoming with claims of NHI without some form of craft or technology that I could present and have hardcore scientific data. In the end, in this day and age of fake imagery and mistrust in government, it is the only way to get disclosure; otherwise NHI might as well be Angels and demons for all we know.