“Against the brute” would probably be “against the devil”.
I’m from an Irish-American family on my ma’s side but they regarded spitting as disgusting and nobody in my mom’s family did that. They would likely cross themselves and say “Jesus, Mary and Joseph help us” or something like that.
I would associate this spitting custom with Italian, Greek, Eastern Europeans.
It’s mentioned in an old hit song by Paul Simon that I liked as a child, “Me and Julio Down by the Schoolyard”. The narrator (Paul Simon) commits some kind of crime with Julio down by the schoolyard, is caught, and then "Mama looked down and spit on the ground every time my name gets mentioned, and Papa said ‘oy, if I get that boy, I’m gonna stick him in the house of detention.’ "