Most cars don't have sharp edges there and there is rubber. I'm pretty sure I've seen a kid get the fingers shut in a door, and it was just a matter of opening it, no injury and certainly no amputation.
It hurt like hell then and for a few hours after, but I guess my fingers at ~7 years old were still slim enough to come out without any permanent injury. There was some rubber padding even on a car that old (I'm thinking the purpose is making the door watertight though).
The Tesla doors look like my fingers would have had no chance. How do we go backwards from something we got right four decades ago? Especially the self-closing hatch which seems to exert a scary amount of force in an area were people will be prone to place their hands.
Simple. By treating car developement like SV SW development, thereby not giving a damn about the past decades of automotive know-how and lessons learned, as that's considered boring and uncool crust, and only focusing on developing new unrealistic and shiny features ("hey look at this snake charger that's coming in 6 months, isn't that cool") that look good on social media to boost sales and stocks prices.
And it works for Tesla because most Tesla and newer car customers in general, don't check stuff like panel gaps, chassis cracks, door seals, panels being attached properly, etc as that's been a solved problem for decades in the auto industry that nobody thinks about anymore would be an issue today, so consumers just focus on looks and shiny new gadgets when buing a new car rather than what makes a car a car.
On the contrary, I (mistakenly) slammed a door from my (now 12-year old) Alfa Romeo to the hand of a relative who was holding on the B-pillar, and it barely touched her hand at all.
Elon works from first principles, so it's going take a while.