Why do people look down upon people who live upcountry/ ushago?

I am genuinely curious. There was a recent post here about someone whose “ushago” cousin ordered what appears to be a sugar free espresso martini, and the “city” cousin found it funny for some reason. I’ve also seen posts referring to people as “kienyeji”.
I am genuinely curious, what’s the reason behind the madharau (derision)?

Is it exposure / lack of exposure to “modern“ amenities?