They do it every time they want to keep inquiring and suspicious people distracted.
Once is an occurrence. Twice is a coincidence. Every few years for the past six decades is a pattern. Nothing ever comes of it but in the end new shit got to happen without interruption.
Like how do these people believe the government can keep aliens a secret but they won't buy that?
Edit, watch AOCs questions in that hearing. She is hot onto the point: she asks specific questions about the process and requirements for reporting phenomenon to Congress. She's doing that because this entire hearing is focused on whether grusch endured reprisals for whistleblowing. That's all they care about, that's what the House Oversight Committee does. And when she gets to the root, Grusch goes anxious, stutters, etc. But when he's talking about his claims it's highly scripted, no stutters, nothing.
Grusch is using the whistleblower protections to grandstand, AOC knows it. He's gonna be facing perjury charges within a month, bet. I'll bet even further, he's gonna flee the country and then claim the warrant they put out for him is "targeted" at him for whistleblowing. Conspiracy con artists all operate on the same script.