That's the point -- that it's too obviously a choice by the writers, since there's no good reason for it to be the case in-story. Everything in a story is the writers' choice, but you don't want the writer's hand to be too obviously puppeteering things, so ideally everything should have a logical in-story reason. This doesn't.
No doubt they wanted this Robot to feel more alien and mysterious. They just went about it in an inconsistent way.
Of course, so did I, but that doesn't mean we can't talk about those details afterward. You're allowed to critique something you loved.
The video of the robot scanning Kelly was time-stamped 12/21/2044, and they said it was about five and a half years in their past. Since the Christmas Star hit 2-3 years before the series began, and the events of the series spanned a couple of years in all, that seemed to be saying that the video was just days before the Christmas Star, that SAR sent Scarecrow on what I'd guess was a kamikaze mission to cause an extinction-level impact on Earth immediately after discovering Kelly. But Kelly had been lost while Judy was an infant, so that would be maybe about 15 years before, give or take. So I was a bit off, it's the late 2020s, but that's still way too close to the present for that kind of technology.
They did say that the new ship (I forget its name) would begin ferrying colonists from Earth again, including "Smith"'s sister Jessica. I don't think the Robinsons have any interest in returning with it, though, at least not to stay. Maureen might go with the ship because it's her baby, and the family might accompany her, but then they'd come back to Alpha Centauri.
