She traveled from Milwaukee to Kenosha of her own volition with intent to kill, shot him twice, burned his house down, and stole a car.
Going to someone’s place uninvited with intent to kill that person is premeditated murder. Burning down a house is extremely reckless, others could’ve been easily caught up or injured in this rampage. Not to mention that the house fire likely destroyed a lot of potential evidence. Other victims might have more difficulty finding their own justice as a result, or worse if he had any accomplices their collaboration could be harder to prove.
Cool motive. Very understandable motive even. Still murder. Vigilante justice is no justice.