It's isolation. Just because both tribes in Nigeria and Liberia for example doesn't quite mean they're the same. The Fulanis are also influenced by the culture of the countries they live in.
Our Hausas in Ghana for example are quite isolated from the Hausas in Northern Nigeria. Even the dialect difference is like comparing NY accent to London accent.
I get that but what is it about "Nigerian Culture" or the climate making folks wild out to the point people try to say that group is "inherently" a certain way? I'm saying if it was true then wouldn't they be wreaking havoc in every nation they are in?