Well then speculation also says that Grusch has been either lying about the whole UFO stuff or has been duped around albeit his own first-hand witness allegations, right? Because the speculation I some times heard that he misunderstood their sources err, I found far-fetched for a man who has a degree (Bachelor, IIRC) in physics.
From what Mr Grusch has said, he hasn't been in a position to examine any evidence that would benefit from evaluation by someone with a physics degree. He hasn't seen any physical evidence at all.
Having a degree in
anything isn't necessarily useful in assessing if someone else's verbal account is reliable, if that account doesn't contain novel, testable information.
Traditionally, the armed forces (and many civil employers involved in technology) had many people in highly technical roles who hadn't acquired a university degree; they gained their proficiencies through apprenticeship-type programs and /or trade-related training. Maybe less common over the past couple of decades. I'm lucky enough to know some (middle-aged) engineers who trained this way whose knowledge in their respective spheres far exceeds that of the average new graduate (also their wider understanding of science/ technology, and indeed general knowledge IMHO).
There are quite a few instances of people with respectable degrees- and doctorates- advancing or supporting implausible theories in UFOlogy, think Jacques Vallee, John Mack. Some religious groups are eager to point to the (tiny minority of) scientists who believe the Earth was created in 7 days around 6,000 years ago. More generally, even well-regarded professional scientists can make- and stand by, at least for a while- howling errors or misconceptions; re. Fleischman and Pons with cold fusion, and Fred Hoyle whose pioneering work on stellar nucleosynthesis didn't prevent him from believing that archaeopteryx fossils were fakes (debunked) and musing that an outbreak of meningitis in a specific small town in England was brought by a comet (epidemiologically silly, and unhelpful).
Right now there will be physics graduates doing their best for the rulers of, e.g., North Korea or Iran, just as there will be chemistry graduates working for drug cartels. As per the wider population (and graduates of all disciplines) there will be
some physics graduates who are mislead by others, who have unusual or erroneous personal beliefs, who falsify results, etc. etc.
(I'm
not claiming that physics graduates are more prone to these traits than anyone else!)
So I don't know if Mr Grusch misunderstood his sources, or if he has been deliberately misled, or if he's reporting an important objective truth that he's been made aware of, but I don't think his having a degree adds weight to any one of those explanations (or any other) being correct.
[Edited, 23:03 to add: Just to clarify, I think it's unlikely that Grusch has found "an important objective truth that he's been made aware of", but that's more to do with general context, i.e. the total lack of convincing evidence of alien craft crashing / landing anywhere, anywhen; the total lack of evidence for any technologies or information of intelligent extraterrestrial origin being used by anyone, and the "believer" assumption that all of the many claimed alien craft are seized by shadowy US agencies (or counterparts in other nations, acting in precisely the same manner) before anyone else can take decent footage or acquire physical parts of the craft, and all the "acquiring agencies" have managed to enforce essentially 100%-effective secrecy for decades.]