You're sure stubborn over a what's still a hypothetical situation, notwithstanding a bit more scientific certainty than before. But the vectors I visualize when you describe the inevitability of a terminal velocity equal to escape velocity don't add up. They're not all perpendicular to the impactee, and a high velocity approaching parallel to the direction of orbital motion (grazing) is 90 degrees to that "inexorable" pull. Add the vectors, man, add the vectors!

Plus, both partners in the dance are large bodies with significant momentum. Rather than a small impactor with insignificant mass, in the case of Pluto and Charon the moon has roughly a tenth the mass of its primary--largest such ratio in the System.

If Charon was captured once upon a time by Pluto, then right there don't we have an example of a non-catastrophic rendezvous between two large free-flying objects? How in the worlds did that happen if two objects in space can't get close without being drawn into a deadly shattering embrace?

My final whack on the horse is to suggest that smaller lumpy bodies that haven't been vulcanized into solid objects by gravitational heating, might be more resilient in an impact, and might give and crumble rather than shatter. A collision of two bean bags rather than two billiard balls. Or even a billiard ball and bean bag.

Consider, grasshopper, that paper beats rock by enfolding it. Perhaps Pluto captured Charon not by shattering it, but by cushioning it. You know, lithobraking. Or maybe I mean cryobraking.