I do get ppl saying its complicated. A lot of people dont know much about servers just as a start? (Not that you really have to to use kbin or lemmy.) or know anything about federation or what it mean in this sense. If you ask them what is meant by instance, most people saying so probably wouldn't understand that in this sense even if English's their maternal language. Not even that those people arent smart, just like just because you dont understand a foreign language doesnt mean youre not smart: this is just an area they dont know about.
I think some people find it strange that people are confused, because maybe they dont often talk with people who arent as familiar with technology, or more used to being on 'tech' related parts of the internet where some people would understand these. It seems this way bc the community of kbin seems to be more into technology, like i seen programmer humor posts get popular a lot, and discussions about linux, and the technology magazine, and stuff like that.
If so i can see why someone being confused would be surprising. But know that: a lot of people probably wouldnt join other social media either if it was more user-driven (in terms of setup? If thats phrased right?) which is why stuff gets more simplified on official websites and app. Is important to remember that many people (even some my own age!) dont have any context for all of this stuff they would need to deal with and decide in order to use Kbin/Lemmy - dont know what is an instance. What is federation. Defederation. I would say its easy to understand once you try, but i know i speak for myself who already has some knowledge and interest about technology and learn fast. And not everyone even wants to use something that required them to figure it out as they go.