One person's "irresponsibility" is another person's freedom.
Lots of people consider gun ownership to be irresponsible.
Children don't have adult freedoms. They don't have 2nd amendment rights as you and I do. Driving or riding in a car is not a freedom or a right. It can be taken away for a number of reasons. Using your logic, DUI laws shoud be removed because it takes away your freedom to be irresposible? You are free not to wear the seatbelt, but you will be fined if you don't.