“If you put everyone’s mouths together in this video, you’d get a full set of teeth.”
This makes zero sense. It’s kind of like someone’s trying to make a point and not doing a good job of it.
He's labeling the crowd (and us) as poor, stupid, toothless rednecks, peckerwoods, hooligans, etc.
Implication: All are tooth-deficient, slack-jawed yokels.