Merriam-Webster lists this meaning.......


Main Entry: ya·hoo
Pronunciation: 'yA-(")hü, 'yä-
Function: noun
Inflected Form(s): plural yahoos
1 capitalized : a member of a race of brutes in Swift's Gulliver's Travels who have the form and all the vices of humans

2 : a boorish, crass, or stupid person
- ya·hoo·ism /-"i-z&m/ noun

I've heard & used the word myself.It has nothing to do with
where a person comes from.