> aren't we really saying voters are not individual agents but rather a mob subject to manipulation by propaganda?

Like we've been saying since the founding of the country? yeah

"The body of people ... do not possess the discernment and stability necessary for systematic government. To deny that they are frequently led into the grossest errors by misinformation and passion, would be a flattery which their own good sense must despise." -Hamilton

The founders did not think that electoral college was a good idea, senators should be appointed and not elected, and only a few citizens should be able to vote generally, because they were feeling mean. They did so because they thought these things and the act of voting itself were simply instruments to produce good government. They rejected a democracy, and favored a republic, for this reason.