The animal who is treated by the doctor will view the doctor as evil, because the animal has no cognizance of what is being done, and moreover, being an animal, it is driven by instinctive impulses that filter its perceptions. That is, even if it wants to believe the doctor is good, the blood of the animal races due to fear and the instinct of self-preservation. The animal cannot control its instincts.
Since we are just animals with intellect, this is what is happening to those who encounter our elder brothers. Fear, ignorance, and animal instinct cloud perception, judgment, and memory.
Police know well that eyewitnesses to crimes are highly unreliable. Facts, evidence, that which can be tested, are empirical. Our perceptions are not.
There is not a shred of actual evidence of the so-called "greys." This is just another hysteria, like the "lizard people" that are supposedly infiltrating society, or the so-called illuminati conspiracy, or—well, you can list a million theories, and not one has hard evidence, because not one of them is true.
Take a moment to think about all the ridiculous things people have sworn were true that turned out to be nothing at all, or at least, were completely misinterpreted. We do this in our daily lives, and we do it collectively as countries, races, communities, etc. Most of what we believe is false. We love a lie. We hate the truth.
Having considered all of this, then consider that anytime people find themselves facing a superior power, or a phenomena they do not understand, they demonize it.
Just look at all the movies and tv shows: all of them show extraterrestrials as evil dominators, as monsters, as insect races or immense automatons driven by evil, etc.
Because of our collective animal mind that is terrified by what it does not understand, we cannot even imagine that the extraterrestrials are far beyond our conception of good and evil.
Anyway, until you experience their reality for yourself, it is a complete waste of time to worry about it. The greatest threat to humanity is not in space, it is ourselves.
“Nothing is easier than self-deceit. For what each man wishes, that he also believes.” —Demosthenes
"Do not worry; cultivate the habit of being happy." —Samael Aun Weor