I had the same confusion so here's my layman's understanding. They are defining capture/orbit as having negative "geocentric energy" which is a term of art no one else seems to use but I think is just a mathematical representation of the following:

> a temporary satellite is any body that enters the Hill sphere of a planet at a sufficiently low velocity such that it becomes gravitationally bound to the planet for some period of time. [1]

again stretching my understanding too far, I think this basically means that in the absence of other celestial bodies the satellite would be in a stable orbit, but that in reality after some time it gets far enough away that the sun's gravitational pull dominates and stops it from making a full orbit.

[1] https://en.wikipedia.org/wiki/Temporary_satellite

Technically The Moon is slowly leaving earth's orbit too, to the tune of 38mm per year[0]. Everything's temporary...

[0] https://en.wikipedia.org/wiki/Orbit_of_the_Moon

Because during that time from its frame of reference it will be falling around the earth until it reaches escape velocity and starts falling around the sun again.

To be fair, it's still kidnapping in most states even if the duration is very short.