Congratulations, you don't have motion sickness. I think that post was referring to those who do.
For those people, rear-facing seats can exacerbate motion sickness. See e.g. https://www.sciencedirect.com/science/article/abs/pii/S00036...
> rear-facing seat of my family's circa 1970 Plymouth Satellite station wagon growing up. Completely unsafe,
I am curious: Unsafe because a " 1970 Plymouth Satellite" or because "rear-facing seat"?
Both, plus absence of seat belts. Rear facing with no head support is a good way to snap your neck if you are wearing a belt, but because we weren’t, we’d probably be flying forward to the windshield.
https://www.automobile-catalog.com/img/pictonorzw/plymouth/1...
Looking at that picture, I see belts, but I do not recall those belts and suspect they were deeply wedged into the seat and forgotten about.
My sister and I would pass the time folding up a piece of paper and each of us got to draw part of a person without seeing what the other had drawn. Sort of like visual madlibs.