For the vast majority of the population, the number of cars passing by their house each day will be many times the number of planes burning leaded fuel flying overhead.
Lab specimens, search and rescue, law enforcement, aerial photography for the "satellite" maps on your phone, power line surveying, transportation to remote parts of the country. Not to mention training for both future airline and military pilots.
Just because they're not economical for passenger service, doesn't mean they don't have an important role.
And again, I don't think you'll find many people in aviation who wouldn't like to move away from leaded gasoline. They're just waiting for the FAA to certify a replacement.
Yes it's bad. Yes we need to get away from it. Yes it's being worked on and will happen eventually. Also please at least recognize that it's a hard problem.