Why have ethnologists focused their study on "nonliterate" peoples?

The reason as to why the ethnologist focus more on non-literate people on their study because mainly of the reason that they are going extinct. The non-literate people are being referred to those societies in which their people does not have the ability of being able to read and write in which the ethnologist studies and help out of.

The reason as to why the ethnologist focus more on non-literate people on their study because mainly of the reason that they are going extinct. The non-literate people are being referred to those societies in which their people does not have the ability of being able to read and write in which the ethnologist studies and help out of.    

Explanation:

the congress was known as inneficient and scandalous.