[Buckeye McFrog]

I don’t think illiterate slaves in 1776 were as utterly lacking in common sense as the people we have voting today.

[NativeSon]

That's because they could not afford to be so careless & lazy.

I can see why 'property ownership' was a requirement to vote. The person is tied to the land/place, has an interest in the future and would seek to minimize encroachments of any kind.