To correct your analogy they are probably thinking more along the lines of:

"I just custom built a car but bought a knock-off car door that has a fake keyhole and no real locks"

"Hey! You've left your car unlocked! I got in with any key!"

"Why were you trying to get into my car?"

Of course the analogy breaks down even further when you consider that the "car" in this case contains stuff(sensitive user data) that doesn't belong to the car owner. Analogies are hard.