In Stranger Things , Billy hates Lucas mainly because Billy is written as racist and violently controlling of Max, not because Lucas actually did anything wrong.

In‑story reason

  • Billy first fixates on Lucas in Season 2 when he sees Max talking to “that kid” in the parking lot and warns her there are “certain types of people” she should avoid, calling Lucas “one of them.”
  • At that point he doesn’t know Lucas at all, so his hostility is a snap judgment tied to how he views Max’s Black friend rather than any real behavior from Lucas.

Racism and control

  • Fans and commentators widely read Billy’s behavior as racist, and the Duffer Brothers have explicitly said Billy is a racist character whose aggression toward Lucas comes from seeing him as “different” and from his general rage at the world.
  • Online discussions repeatedly boil it down to “because Lucas is Black and Billy is racist,” pointing to how he targets Lucas first when he storms into the Byers’ house and tells him to stay away from Max.

Billy’s home life and personality

  • Billy grows up with an abusive, hyper‑controlling father, which shapes him into someone who tries to control Max and isolate her from friends, especially boys she likes.
  • That background helps explain how he becomes so cruel and explosive, but the show still presents his hatred of Lucas as a mix of racist prejudice and toxic, possessive control rather than any kind of justified “protection.”

What forums and fans say

“Because Lucas is Black and Billy is a racist. Plain and simple.”

  • Reddit threads and fan posts largely agree that while you can analyze Billy’s trauma, the specific reason he goes after Lucas so hard is that he’s a racist bully, and Lucas happens to be the Black boy dating his stepsister.
  • Some fans also note that Billy is hostile to Max’s whole friend group, but his language and focus on Lucas show an extra layer of racially motivated hate on top of his general abuse.

TL;DR: Billy hates Lucas because the character is designed as a racist, abusive stepbrother who wants to control Max, and Lucas—being Max’s Black boyfriend—becomes the main target of that bigotry and rage.

Information gathered from public forums or data available on the internet and portrayed here.