Something weird about the Dutch Christmas

I work in a Brazilian city called Castro, a place known as the living place of many dutch descendents, that still keep their ancient traditions.
Some days ago, after work, me, my coworker and her family went to a famous restaurant in the city, and when we arrived, there was a Dutch birthday party happening there. As Christmas was near, there was a Santa Claus and his helpers in the place. And here comes the weird thing about it. The Santa Claus helpers were not elves, as we used to see here in Brazil, but... black people! Actually, not real black people, but white people (Dutch descendents) painted black and wearing afro wigs.
As it seemed so weird to me, after I got home, I started to seek explanations for it. Searching on Google, I figured out that in Netherlands they don't have the same Santa Claus we have here in Brazil, but they have San Nicholas, who was a kind of ''original Santa Claus'', and, according to  Dutch Folklore, he has black helpers.
Although haven't read anything specifically about it, it seems to be a heritage from black slavery. As San Nicholas has been a traditional Christmas character for so long, and in the past so many people in the Netherlands had black slaves, maybe it seemed natural for San Nicholas to have his ''black slaves'' as well.
It might be something tradional, but it still seems a very weird and racist thing to me.