Edward Snowden is a whistleblower, Daniel Ellsberg was a whistleblower- both broke the law (Snowden currently lives in exile, while charges against Ellsberg were dropped due to legal improprieties committed during his trial) to take what they discovered directly to the American people. Both paid a price.
David Grusch however has not broken any specific law, amazingly he's managed his in house expose all by the book, and still retains his top secret military intelligence classification- which is why he often speaks publicly in generalities (he has given much more detailed testimony to Congress behind closed doors). He must first get clearance from his former/still boss on what he can say and to whom, otherwise, off to jail he will go- for a very, very long time... He has gone out to the very edge of the precipice, but he has not taken the leap- at least, not without a parachute. And I can't much say I blame him, I wouldn't particularly want to sabotage the rest of my life at his age, with a lifetime of even more debilitating harassment, decades of jail time or a fatal "accident." He's already gone well above and beyond.
Prior to appearing before Congress, he had to testify (under oath) to the Inspector General, who then interviewed other military/government officials under oath concerning Mr. Grusch. All this to ascertain Mr. Grusch's character and credibility (before being pilloried by large sections of the government, press and public as just the latest tin foil UFO whacko). Mr. Grusch is more witness than whistleblower; and as Mr. Coulthart curiously reminds us, US courts have had no problem sending people to their death on witness testimony.
I don't think the current testimony from Mr. Grusch will lead us directly to the much anticipated Disclosure where all will be revealed to the public at large. It will simply let (some of) the secret(s) out to a larger ring of government officials (ie- select members of Congress, etc) so they can cash in. But it does get us one step closer (perhaps now sooner rather than later), until real whistleblowers decide to one day forgo their jobs, pensions, freedoms and personal safety to take that extraterrestrial leap of faith. It's gonna happen, just wouldn't hold my breath...