> There is no text which codifies it, unlike Islam.
Each sect has a different Quran, different Sharia, different precepts. There are massive differences in the way Islam is practiced across the world.
> Unlike religion, its not voluntary.
Imagine then someone who openly claims to be an artist and that creating art is a part of them. Would you say this person culturally associate with a murderer who kills "for art"? Both call themselves and associate with the artistic work.
> I would say a better analogy would be a white man associating himself with black gang culture by getting gold teeth, gold chains, tattoos,etc to a job.
I don't think that it is a good analogy, as that white man associate concretely to black gang culture.
A better analogy would be, a man who associate with black culture in general but gets rejected because his employer consider him to associate with black gang culture although he claims he doesn't.