Dear Chris Brown (again),
In case my last letter didn't work for you, let me try again.
You're hanging out, tweeting, when someone says, "You're a worthless piece of shit."
Naturally, your response is to wonder, "Whoa, what's up with her?"
But then it kicks in: oh, right.
You're probably frustrated. People keep bringing up your felonious past when you'd rather put it behind you. It's aggravating. You feel harassed and misunderstood.
Chris, these aren't simply haters. They're not antis who jump on you just because you're a public figure. As I reminded you earlier, it's normal and reasonable for people to talk about your history and to find it relevant.
So, here it is: someone calls you a worthless piece of shit.
You resent the insult, but you know why she said it.
If you don't want to hear it, you can block her. If you think that she's harassing you, you could contact Twitter and push them to deal with it. If you're upset, you can employ any of the techniques recommended in anger management. (I assume that you've been through anger management therapy, or therapy in general. I also sincerely, not sarcastically, recommend that you go back for more.) If you want to reply to the insult, you can suggest that her remarks are inappropriate by tweeting back something like, "Hey, I'm just trying to talk to my fans, here." If you want to address the more general point that you want people to stop bringing up your criminal past, you can say, "I've done some terrible things, and I'm sorry for them, but I deal with that every day. I'm working towards being a better person. #secondchances." That's not 140 characters, but you get the idea.
If you want to trade insults, I'd recommend strongly against it for a dozen different reasons, but you could reply in a tit-for-tat fashion. She calls you a worthless piece of shit, you call her a untalented jackass, and so on. Point out that you're more wealthy and famous than she is, something like that. "Who are you? #questionfromaGrammywinner"
You skipped all of those routes and went straight for crude, sexual misogyny.
If you want us to believe that your abusive behavior is in the past, that it's all behind you now, that you're not that person anymore, you have to stop being that person. People have a problem with you because you have a problem with anger management, misogyny, and domestic abuse, and when they bring it up, you react with more of the same.
If you're angry that people treat you like someone who abuses women, stop acting abusive towards women. Work on how you respond to women. Work on how you respond when you get angry. Your responses are all out of proportion to the situation. Your responses are grossly misogynistic. This is a problem. You have a problem. Don't be surprised when someone points it out.