On this blog, I do not shy away from the direct parallel of Max copying Neil's verbal and physical abuse when she confronts Billy in the Byers' house. I'm going to be breaking down the clips of Neil and Billy vs. Max and Billy. If you want to view these scene clips, watch Neil and Billy here and Max and Billy here.
Neil: What did we talk about?
Billy: [says nothing]
Neil: [hits Billy across the face]
Neil: What. Did. We. Talk about?
Billy: Respect and responsibility.
Neil: And then, he's gonna go find his sister like the good, kind, respecting brother that he is. Isn't that right, Billy?
Billy: [says nothing]
Neil: ISN'T THAT RIGHT?
Billy: [quietly] Yes, sir.
Neil: I'm sorry, I couldn't hear you.
Billy: [louder] Yes. Sir.
Now, here's Max's exchange with Billy, which directly mirrors Neil's abuse toward Billy:
Max: From here on out you leave me and my friends alone. Do you understand?
Billy: Screw you.
Max: [Slams the nail bat between Billy's legs]
Max: SAY YOU UNDERSTAND. SAY IT. SAY IT!
Billy: [quietly] I understand.
Max: What?
Billy: I understand.
Analysis
What we see here is Max matching Neil's abusive patterns to assert power and control. The match is undeniable. She, like Neil (in Exhibit B), lays out what she wants Billy to do and finishes with a question that pushes for Billy's compliance to her wants. (Neil wants Billy to find Max and asserts that want with: "Isn't that right, Billy?" / Max wants Billy to leave her and her friends alone and asserts that with: "Do you understand?")
When Billy says, "screw you," and doesn't give her the answer she wants, Max slams the bat between Billy's legs. This runs parallel to the moment Neil hits Billy in the face (in Exhibit A) when Billy doesn't answer him.
After she threatens with violence, she yells and demands an answer: "SAY YOU UNDERSTAND. SAY IT. SAY IT!" just like Neil yells and demands an answer: "ISN'T THAT RIGHT?" When Billy says, "I understand," Max does what Neil does. One verbal statement of compliance is not enough, especially when the verbal compliance comes quietly. It needs to be rubbed in. Enforced. It needs to establish (firmly) who is in power and who is not in power. And so Max says, "What?" just like Neil says, "I'm sorry, I couldn't hear you." It forces Billy to say he understands... again.
And the thing is that Max says she doesn't want to become like her brother after acknowledging that she's angry and a jerk like him, too. This is also another sign of what I talked about before in that Neil has gaslit Max and manipulated her like a chess piece to pit Billy and Max against each other (read more here and here). He does this to retain his power because if Max and Billy were aligned, Neil loses power. So Neil makes Billy the caretaker of Max, which makes them harbor resentment toward each other. It makes Billy and Max angry, place blame on each other, and fight-- all while Neil continues with his abuse in a broken household. And Neil's mental manipulation on Max worked to the point where she believed that her greatest concern is becoming like Billy. This is incorrect on her part. Her greatest concern is becoming like Neil, the real monster in their lives. And we see that come to a head when she ends up copying Neil's abusive behavior.
But there's other forms of abuse going on here, too, namely emasculation. I've spoken before that in the Mayfield-Hargrove home, "masculinity" is strength, power, and control. This is partially why Max chooses "masculine" presenting style. She is witnessing what is considered "feminine" as weak and what is considered "masculine" as strong and absorbing this behavior to present herself as strong (read more here).* Billy does this, too, by hyperinflating an image of masculinity to establish a sense of strength and control (read more here and here). More on that later.
Neil's abuse is about control, and one of the ways he does that is to emasculate Billy. We see flashbacks of Billy's childhood where Neil tries to degrade him (i.e. when Billy doesn't want to play a boy's sport-- baseball-- Neil asks if he's raised a pu***). But in the specific scene between Neil and Billy in S2 linked and quoted above, Neil says the following when he's questioning Billy about Max's whereabouts: "So that's why you've been staring at yourself in the mirror like some fag*** instead of looking after your sister?"
What does that do? Neil is trying to knock Billy down right away-- to establish that Billy's weak because he's not "masculine" enough. Max achieves the same end when she swings her bat and connects with the wood right between Billy's legs. It's an effort to emasculate, which, again, in the Mayfield-Hargrove home, is synonymous with weakness.
And then there's Max injecting Billy with an unknown drug in the neck. I'm not a medical expert by any means, but I do know your neck has major arteries. The chance of Max hitting an artery and therefore pumping some unknown drug directly into Billy's heart is pretty high, especially when Max is just blindly stabbing this needle into him with no experience. Really, if we're being honest about it, Billy should have died, or at the very least, he should have gone into some type of narcotic shock. And since he was left there, passed out on his back, and received no medical aid, he still would have died. He doesn't die, because this is a tv show, but we do have to pause and acknowledge the reality of the action of stabbing drugs into his neck like that.
Now, with all that said, yes, Billy is also copying that same abusive behavior from Neil to Max. When they're driving in the Camaro and talking about how they're stuck here in Hawkins, Billy and Max fight about who is to blame for the move:
Billy: And whose fault is that?
Max: [quietly] Yours.
Billy: What'd you say?
Max: Nothing.
Billy: Did you say it's my fault?
Max: No.
Billy: You know who's fault it is. Say it. Max... Say it. SAY IT.
It's the same pattern. A question, a quiet response that's not deemed good enough, followed by more questions and a demand to "SAY IT!" To me, this drives home that Max and Billy saying and doing these things are not Max and Billy's own voice/words. It's Neil. They're both copying Neil. They're both so controlled and defined by Neil's abuse that the line between who they are and who Neil is becomes blurred. They don't know how to heal without yelling and fighting and violence because it's all they know.
*Additional Note: On the topic of Max witnessing what is considered "feminine" as weak and what is considered "masculine" as strong and absorbing this behavior at home, I do want to bring up another point. It is absolutely clear that this scene is showing a direct parallel to the way Max is copying Neil's behavior. But I think it's also worthy to point out that Max is so hyper-attuned to boys and men and mimicking their behaviors that she even mimics Steve, who she's known (at this point) for a few days. Earlier in the series when they're in the bus, Max watches Steve grab his nail bat and stands between her and the other kids and a demodog. What does Max do at the Byers' home? She grabs the nail bat and stands between her friends and Billy. The point of this being she is identifying what boys and men around her are doing and doing it herself. She's watching. She's copying. All the time. Inside or outside the home. She copies Billy, too (more on that later). It doesn't make the parallels in this scene less important to discuss; rather, I think it gives us a little more insight on Max's frame of mine and how abuse is affecting her choices.