Most European brands I've tried only lock the cars when the speed exceeds 20 km/h.

In addition, most brands I'm aware of will unlock the car when the airbags are deployed (Kia/Hyundai, Renault, Volkswagen, Mercedes, BMW). Because these cars still have door handles, they can be opened by a bystander after a crash.

The issue is not that the doors are locked. The issue is that unlocked doors without door handles are still useless.