This might shock you but cars where open source for years. Did you think those super detailed shop manuals anyone could buy where not intended to be used to work on the car? How about the massive aftermarket and any and all hot rods? This idea that you can’t fuck with you own stuff because its got a computer in it for “safety” is relatively new. Does no one else remember hooking a laptop up to the old ECUs and modifying how the engine works?
The issue is normalizing the concept that you do not get to control what you paid for. Responsibility has not changed, you can drive your car into a crowded park and would still be guilty of it regardless of how stock it is. If you mod your stuff to be dangerous that would be a crime. In this case would you say that remote starting your car from your phone somehow is a public safety issue? At least if you jailbroke it to work on your own network?