Is Senator MItch McConnell Saying that Most Americans are Idiots?

Probably not, because not impugning voters is something that Republicans (and in particular the far right, from which framework McConnell emanates) tend to be much better at than Democrats. Still, Either he is saying this (unlikely), or he is being misleading or illogical (take your pick).

Mitch McConnell:

I think it is perfectly clear that most Americans will treat the vote to get on the bill as a vote on the substance of the bill. So our view is that cloture on the motion to proceed to the bill is a vote to endorse a half a trillion dollars in Medicare cuts, $400 billion in new taxes, and higher insurance -- health insurance premiums for everyone else.

Putting aside McConnell's highly questionable framing of the health care bill, a vote to avoid a filibuster is not a vote in favor of Health Care. These are two entirely separate things. McConnell says most Americans -- perhaps taking their cues from him? -- will, falsely, view them the same.