It's infuriating. He talked to 40 people, some "very high level", which is ambigious sure but Grush himself was a Colonel equivlent when he was in the NGIA, but there is a significant amount of people inside the government who are directly telling Grusch we have this stuff. He gave the ISG all the evidence (documents etc) names, interviews etc. The ISG declared it an urgant concern (this is apparently seperate from the retaliation claims).
He goes and gives a summary of this stuff to congress, and random normal people say "oh there's no evidence", but he clearly HAD IT, AND gave it to the ISG. Congress asked to see it, and have been denied. Why are they being denied if there's nothing? How can congress properly perform their function of oversight if they keep getting denied requests?
What's frustrating is there's a sector of the government that seems happy to say "we haven't see any evidence, must be nothing" while at the same time the government is refusing to share the supposed evidence.
I think in 2017 I would have been one of the skeptical people, but the more I watch this play out, it's cystal clear there is something and there is a group of people in our government who want it out there, and a group of people in our government who absolutely do not.