I don't know if White dudes ever just decide to assault some woman on the street in crime of opportunity.

The bottom pits of white trash absolutely do, but that's part of poverty making men much more equal. I've seen it happen, usually while they are drunk or high as a kite, and its awful for everyone because 50% of the time if you "help" she will turn on you for hurting "her man." I think anyone whose family comes from the trailer park either has a few of those types of men either in the clan or living near them.

The roving packs and obscene violence aspect however is not very common to the non-browns. Its usually entirely an angry lowered inhibition move, rather than a stone cold sober brutality.