When making complex decisions affecting the lives of millions, or handling issues that require deep subject matter expertise, is an educated upper middle class not better at making decisions than an uneducated lower class? (or any uneducated person)?

That isn't to say the lower class has no say in their government - it is why "democracy is the worst form of government, besides all the others". But having an intellectual, technical team of "trying-not-to-be-partisans" helping elected officials make decisions is a good thing, and you make it sound like a bad thing.