A lot, if not Most people who practice hoodoo and american voodoo are Christian. Their not going to replace religion for religious people.
My Grand uncle who was a Devout Christian, would take trips to St Mary to see an obeah man when he was ill. Would come home healthy af. Had me looking like
And their not something you should "get into" just because of your "heritage." If you are not mentally strong this stuff can mess you up.
My brother won't even go inside our grandparents house anymore, do to the nightmares he used to have during his time learning from our grandma and aunt. Just the thought of that house gets him shook, and he's in his late 30s.
I can't speak for Santeria, ifa, or Haitian voodoo.