What Is "Familia Affection"? (Law)

I heard this phrase and was wondering what it means exactly. I tried to Google it but I came up short. I am probably spelling it wrong.

I got it from the great Australia soap opera “Prisoner” (“Prisoner: Cell Block H”)

Toni McNally killed Roz’s mother. After McNally got off at her trial, Roz turned around and killed Toni McNally.

Roz thinks she’ll get off and the court will understand. Vera, one of the warders says “Familia affection does not constitute a defense.”

I’m assuming it’s some kind of summary justice type of thing, but I was wondering exactly what it means

Familial affection means loving your family. It’s not a legal term. The warder’s saying, basically, “You’re not allowed to kill somebody just because they killed a family member you liked.”