They most certainly can. We just prefer to think of them as light skinned.
Scientifically speaking, the genetic origin of all humans living today is in Africa. So it is not a question of whether White people are naturally entitled to the Vodun or not. The big issue around it is mostly cultural, and for adherents to the idea of human biodiversity, capability of understanding Vodun.
I can’t say that all people of European ancestry can get it, but certainly some can. Those who do get it, same as Black folks, get it through their Ancestors. Rather than co opting Vodun, they learn the Vodun and various ways of honoring them, and then apply that to their spirituality in a way that honors their own Ancestors.
As an example, let’s say a person of mostly Nordic ancestry begins to have dreams and visions that are clearly from an Orisha presenting themselves in African form rather than “translating” their appearance to a Nordic one. This likely means that there is something in Vodun they need to learn that they might not otherwise get or understand. It is usually that they need assistance from an African because some knowledge has been lost to Nordic people that is still alive in Africans.
Some apparently European people though, actually need to go through the conversion to Vodun as a faith. It could mean that they have an African Ancestor who they are aligned with somehow, and this Ancestor wants them to basically be African. It could also be that they are not going to get what they need spiritually anywhere else.
The problem is that though the Spirits, not humans, choose who is going to serve them and how, humans do have issues and hangups. There is the external opposition to White faces in Vodun, and there is also the massive cultural and social chasm between Europeans and Africans. In order to fully embrace Vodun, a White person has a longer and more perilous road to travel than someone who wakes up Black every day of their lives.
As someone I don’t remember said long ago, a White person can put on a suit and be acceptable in western society. A Black person, no matter how well dressed, is still viewed as a n*****. That is in the diaspora. In Africa itself, most indigenous Africans do not trust White people, and for good reason. This may not be something to feel particularly bad about though, since Europeans often do not trust certain other Europeans, and some Africans often don’t trust certain other Africans. There is tribalism everywhere.
You should consider though, how you would feel if you met an African who told you they were having dreams about Odin, and they felt they were called to Asatru.
One of your first questions would be if they were mixed. If their answer was no, you would wonder whether someone was simply adding to their perspective or running away from their ancestry.
Like a person can’t solve the problems with their spouse in the arms of another lover, you won’t solve issues with your ancestry by running to a different culture. Though the Orishas belong to everyone, African culture belongs to Africans. Be mindful of the lines, so that you don’t disrespect your own Ancestors or someone else’s.