Northern WI, where I lived before moving downstate, had a lot of militia and White Supremacist groups.
I haven't seen much evidence of organized groups down here, but then again, I haven't really looked for them.
Milwaukee is sort of your typical Rust Belt city, so lots of formerly middle class blue collar families, most of those were white. Milwaukee proper has a large Hispanic and Black population. They live in segregated neighborhoods known as "the Barrio" and "the Ghetto", which tells you a lot about white attitudes right there.
There is not a large Jewish population in Milwaukee, most fled to the suburbs and out of state many years ago.
There are quite a few Muslims, many belonging to splinter sects, and we have a Sikh temple in Oak Creek that many might have heard of as it was the site of a shooting where several Sikhs were killed and more injured. Why? The shooter saw the turbans and thought they were Muslims.