My brother yells at me and I get in trouble?

So, my brother is 22, and I am 20. We are at home for the summer, and my grandparents are coming to visit today. A few minutes ago, I was in the shower, singing (albeit quite loudly) My brother starts SCREAMING at me at the top of his lungs for me to shut up. See, I DON'T put up with that. You either be an adult and ask me politely, or I'm just gonna keep singing. I don't think he should be taught that anger and screaming gets you what you want. In all fairness, he apparently was sleeping, and I woke him up. (Which I was not aware of) My dad then comes and bangs on my door, telling me to be quiet. I just think it's ridiculous that my parents condone my brother's behavior, and don't reprimand him, letting him think that it's okay to yell at me. My dad even said something to the effect of: "You're the reason he's angry, so it's your fault." Upom getting out of the shower, I let my parents know that I will not be cleaning anything until my brother apologizes or at the very least gets in trouble. Am I being ridiculous? Why does he get whatever he wants by yelling, and I get in trouble for it? I just don't put up with letting people get whatever they want because they are angry and scream about it. No, be an adult. Ask me to be quiet like an adult. I'll admit, it was childish of me to keep singing, but why should my brother learn that he can scream at me, be aggressive, and get what he wants? I WILL admit that he is not entirely to blame; I just don't get why aggression is rewarded in my family.