Looking at this socio-politically:
I would say there is generally a reaction to Western European Christianity.
On the other side of things, there are many Rastas who are Friendly with and/or member of The Ethiopian Orthodox Tewahedo Church, where Christianity has existed since Christianity has existed.
So maybe this helps you understand what I mean about WEC vs EOTC?
Rastafari doesn't have a finite structure, it's a very personal endeavour.
And in that, there is a lot of breathing room.