Yes in fact there are laws, in the United States at least, that are specific to people being killed with a car.
For example, vehicular homicide, aggravated vehicular homicide and vehicular manslaughter are all laws related to the killing of another person by using a motor vehicle. Because the use of vehicles is already regulated by laws which include standards for their sale, registration, use and those who are allowed to use them.
Sorry, you’ve provided such an obviously poor example.
As for guns, those are regulated too. And if someone uses a firearm to kill others, there are laws that are specific to the weapon itself (assault weapon bans, or the use of a silencer, for example) as well as other laws that govern access to the weapon (red flag laws, child access prevention laws, domestic violence or other restraining orders) which may come into play, depending on the specifics of the case.
So maybe in the case of these apps, just like with guns and cars and rat poison and other examples that have been used in the increasingly tedious replies by some in this thread, society has recognized that not all apps are good or safe and that maybe they deserve the extra scrutiny and regulation they are receiving, simply because of what they are. And that those who provide commercial access to apps, most notably through through the creation and maintenance of the App Store and the Google Play Store, have every right to say no thanks, they’re not allowed here.