I'm not sure why they tend to be more aggressive towards males....we've raised thousands of birds over the years and it seemed that peacock, swans and turkey males all tend to be the most aggressive of all the species..I think it probably has to be some sort of territorial instinct within the males...like dogs! Except for when the hens have nests, then there is aggression but that's really it..
as far as charcoals not living as long, I'm not sure! We always had a bit of a struggle with our white peacocks living a long time but they seem to be pretty flighty like the javas as well.