The infiltrating to invade makes no sense at all.
Human form is so desireable they want to make it their own!
What a joke.
I could come up with any kind of scenerio just as viable.
Like this one.
At sub light, decades to centuries for intersteller travel.
Can't support a colony on technical level across that bridge.
So you inhabit worlds by starting them off at cave man subsistance level.
Let them develop their own technology over time.
And the local biology migh be incompatable for food and germs.
So you modify a local species to develop intelligence.
Collect samples to assist in establishing intelligent species on other planets.
Or this one.
An off world bio engineering firm aquiring raw genetic material.
One argument is that repeated abductions are unnecesary.
One genetic sample, and you know all there is to know of a species.
Genetic switches and triggers have to be evaluated within their environment.
So it would take a long term study to understand all the switches and interactions.
To study and understand the emergence of civilizations and their biology.
To understand how a primitive society develops on another world, is to understand our own emergence.
I could come up with many possibilities that would make more sense than invasion.
But one thing I am sure of.
When you have absolutly no physical evidence analysis, anything you theorize has to be wrong.
Cause you have no clue about what it is that you don't know anything about.
Visions of alien abduction are built into our gene code.
A mind trick evolution plays on us, just one among many others.
A drive of developing technology as a competative, we need to catch up to a technically superior race, scenerio.
Because competition is what drives innovation, and when none exists, nature provides an illusion that there is.
Perhaps intelligence and technology is natures latest experiment to develop a species that can overcome extinction events.
Our climate controlled nests store food, have fresh water and energy, waste disposal, and are weather resistant.
We build better nests that any other species that has ever had to cope with climate change and natural disaster.
When all you have is ancedotal and no physical evidence to test, it could be anything.
Any conclusion you make is premature, and is almost guarenteed to be wrong.
And Jacobs conclusions, make less sense than any one of dozens we could imagine.
Why bother with conquaring by such a slow process.
Superior technology rules.
Enslaving us by erasing our technology would be simple.
Erasing us as a species even simpler with superior biology.
Would take about 6 months maximum.
All of the above has to be wrong.
Cause we don't have a clue.
Whatever works, use it.
A good idea stands on its own value independent of authorship.
If it stands or falls on the credibility of the author, maybe it isn't such a good idea.