'In fact, the author has heard from serious U.S. SETI researchers that they are convinced that “men in black suits” will appear at their laboratory door the moment a detection is confirmed.'
Source: https://arxiv.org/pdf/1701.08422
This basically is just demonstrating how people very very good in their field can still fail Civics 101. Men In Black were some funny movies back in the day, but they were just movies.
"The term is generic, as it is used for any unusual, threatening or strangely behaved individual whose appearance on the scene can be linked in some fashion with a UFO sighting."
Some stories dont even posit them as being from the government, just designed to give that impression. Some reckon alien hybrids. Even in the MiB films they were separate and just controlled the government largely.
https://en.wikipedia.org/wiki/Men_in_black
Its a general fear of government intervention.
If you are asking on what legal basis this fear is founded. I don't think there needs to be one. Lots of governments do illegal stuff. Suits are the classic G man look. They dont need "Jurisdiction" to dress in a suit and harass SETI.
So, that most SETI of all SETI people, Carl Sagan posed the role of the security apparatus in Contact, in the form of NSC head Michael Kitz. The film version gace superficial treatment - Kitz locks down message data, and at the end repudiates Arroway’s visit. In his book version, however, the state apparatus is much more insidious. The astronauts (plural, multiple countries rep’d) are threatened with having their psychological reputations destroyed if they ever utter a word that their encounter ever actually took place, or contravene the governments’ (plural) line that the intended journey had failed. Arroway takes extraordinary measures to make sure her hidden testimony will get out ‘should anything happen to her’. Sagan had a security clearance. One is left with the impression that maybe he wasn’t just making up conflict for dramatic reasons.
The laws of physics are what they are, and governments keep things secret to avoid giving their playbooks and sources of information away to adversaries, not because they've re-discovered magic.
The look is explicitly styled on 1950s OSS goons. CIA/FBI would be the modern equivalent. They seem to exist.
Government secrets can be super mundane and still angering the wrong people can lead to abuse.
IIRC Brian Toohey "leaked" information that was on the public record in the USA. The Australian government still pursued him over it. IIRC the claimed harassment campaign has strong overlaps with Men In Black shenanigans.
Hypocrisy is the tribute vice pays to virtue, and at least to this point, the Executive Branch cannot get away with "classified" actions within the United States that can't be defended in court under the color of unclassified black-letter law. Even FISA is, in fact, a Federal court. And all the ooga-booga supposed uber-secret SOF units that allegedly exist are military units (to the extent they actually exist), which can't be used domestically under Posse Comitatus. Domestic law enforcement is the FBI's job. No ooga-booga secret CIA unit would have any remit to operate in the US against Americans, especially given the well-known FBI/CIA rivalry.
There are no "Men in Black." It's a fun movie premise, that's all.
Right so we got here eventually, you are arguing legally.
So it isnt that men in black suits dont exist (they do) its that they can be legally be prosecuted if found to be acting outside of their jurisdiction.
The issue is that law isnt reality, its not even a sideways glance at reality. People in power do things and then only regret them if they are held accountable at a later date. Which is often not the case.
It makes absolutely no difference if the guy in the black suit is a local cop cosplaying, government goons above their station, or actual black hats working illegally in the wrong jurisdiction, this shit happens.
Dont take it from me, take it from noted conservative writer Robert A Heinlein “government is a living organism. Like every living thing its prime characteristic is a blind, unreasoned instinct to survive. You hit it, it will fight back.”
So we can read the GP quote.
'In fact, the author has heard from serious U.S. SETI researchers that they are convinced that “men in black suits” will appear at their laboratory door the moment a detection is confirmed.'
As "We think we would be placed under extreme government pressure when a detection is confirmed through both legal and illegal means"
Its not the same as "SETI claims MIB is real" or anything.