Doors on cars are set to automatically lock once you start driving because of safety.
When you get into a wreck and the airbags deploy the door being locked shut is supposed to help absorb the impact of the wreck and save you in the event of a crash.
Still you can be severely injured or killed in a crash even when the doors are locked and shut.
I hate the doors automatically locking as well and wish I could find out how to disable them because when I get into my car and start driving and the doors lock I unlock them right away because I hate being locked into my car in case I need to get out of the car quickly.