I would suspect that one cause of uneasiness that some people have towards older people is due to the de facto age segregation practiced by much of this society

I would suspect that one cause of uneasiness that some people have towards older people is due to the de facto age segregation practiced by much of this society up through the end of college. I know that I personally barely had any experience interacting with people more than a couple years older than me well into my twenties, excepting teachers and parents. Even once one finally does get exposed to people of all ages, with some people it may take years for this uneasiness to wear off.