What does "自古蓝毛多苦逼" mean?

动漫里蓝色头发的角色大多命硬悲惨，生活苦逼。于是蓝毛就成了苦逼角色的形象代言

ENIn anime, characters with blue hair are mostly destined for a tragic and miserable life. Thus, blue hair has become the image representative of a miserable character.