why do white people think that all black people can use a turntable?

i was at this houe party and im just chillin sippin on a beer and this random white guy comes up to me and ask if i can be the dj bcuz there dj left i was flattered but at the same time i was loling in my head bcuz i dnt even kno how to use a turn table

Well, unless you actually ever spoke with every white person, you would know that we don't all assume.
I certainly don't make assumptions. No moreso than I would amonst my own race, or any race.

Sounds like you were just dealing with a dummy.