If only the careless drivers were those crippled or killed by their poor driving, it'd be a self-resolving issue as you imply, and nobody should care. However,

If only the careless drivers were those crippled or killed by their poor driving, it'd be a self-resolving issue as you imply, and nobody should care. However, what actually happens is that careless drivers often cripple or kill innocent bystanders in other vehicles as a result of their poor driving. That's why seatbelt laws and improved vehicle safety features are a good thing.