Why is my brother mad at me? Wasn't it his fault?

today my older brother(he's 20) had to pick me up from my friends house today, wll let me just say that my older brothers(the other is 16) they don't really care about me and their always making my life miserable whether it's torturing me or turning my relatives or friends against me. Well my oldest brother came to pick me up in his car and since he's an idiot he tried to drive away while I was opening the door, and because he did that I tripped and spilt my soda ALL over the passenger seat and that made him angry.....i mean pissed. I was scared to get into the car with him but when I did he looked over at me and then quickly slammed my head againt the window and it really hurt(my eyebrow started bleeding). Then we my eyebrow started bleeding he started shouting at me telling me I'm ruining his car. When we got home before I could get out he grabbed me by my shirt collar and pulled me out over the driver seat(it left a huge mark on my neck and it even ripped my shirt) and then he grabbed my arm(his nails were digging in to my skin) and told me that if those stains do not come out(which they won't) that he swore on his life that he will kill me. I don't understand why is he mad at me? He's the one who caused it....i should be mad at him for leaving a huge cut on my eyebrow.