The Founders COULD have set this all up quite simply, Majority rules etc. You vote straight out for your representative and that is the end of that. But, they didn't. Why not?
Because they feared the will of the majority suppressing the minority, so they installed very clear attempted safe guards to separate the people from government elected offices, with the one exception.
That is why this difference between a democracy and a republic is so important. They may have been wrong, but their intent is abundantly clear, to find ways of protesting us from majority rule by the masses.
These were educated men, wealthy in many cases, they did not trust "the masses".