Cars are obviously not weapons, they are vehicles. The definition of weapon is something which primary use case is to kill or maim. The primary use case of a car is transportation.
Do you say that a pencil is a weapon? You could stab yourself by accident with a pencil.
If you use a pencil to stab someone, yes it's a weapon. If I use a shovel to kill someone, it's a weapon. If I use a pillow to suffocate someone, it's a weapon. If I drive a car into a person and kill them because I don't feel like following the rules, yes it's a weapon.
Cars not only have the direct immediate effect as weapons (i.e., using them to drive into/over people), but they also have significant second and third order effects such as the pollution from emissions, tires, production and supply chains, destruction of the environment from road construction, cement production emissions, and so on and so forth. There are also the health effects of people forgetting how to use their bodies to move themselves, being isolated inside an insulated box such that nobody interacts with those around them, which leads people to be hostile, aggressive, violent, and so on.
Cars are obviously not weapons, they are vehicles. The definition of weapon is something which primary use case is to kill or maim. The primary use case of a car is transportation.
Do you say that a pencil is a weapon? You could stab yourself by accident with a pencil.