No. Jargon is a shortcut. The concept behind the jargon is what is essential. It's a lot simpler to say "I stalled the wing" than it is to say: "I increased the angle of attack of the wing to the point where flow separation occurred."
That use of the word 'stall' is certainly different than its use in an automotive or equestrian context. It's jargon.
But the word 'stall' isn't essential. What's essential to understanding is the aerodynamic fact that if you increase the angle of attack of a wing, eventually there will come a point where the airflow over that wing separates from the surface of the wing.
It doesn't really matter what you call a stall -- mushing, separation, high alpha + regime. It's still the same thing, and still needs to be studied the same way, using a valid null hypothesis.
It doesn't really matter what you call a flying saucer -- UFO, alien craft, Fred. It's still the same thing, and still needs to be studied the same way, using a valid null hypothesis.
The Ufology argument seems to be "If I define this jargon word in a clever-enough way, people will have to admit that I'm right in my belief that flying saucers exist."
Justifying a pre-existing belief is pseudoscience. Science tries to show that its pre-existing belief isn't true. That's why science requires a falsifiable null hypothesis.