this "This means that Vegas wants equal action on both sides, so they can win on the vig" is what Vegas always wants.
I somewhat disagree. I don't think they ALWAYS want equal action on both sides. I think they MOSTLY want even action on both sides. I think it's easy to predict how the public is going to bet, especially in the NFL and on "public teams." Therefore, Vegas may set a line on a specific game that will generate lopsided public action. Public teams (the Dukes, Cowboys, Yankees, etc. of the sports world) generate uneven handles at sportsbooks. They know this, and may set the line slightly off a bit, to encourage Joe Public to bet away. Books will then undoubtedly lose to the sharp bettors in that spot, but the public money is more than enough to offset it. In random games like Tulane/UCONN on a Wednesday night in Jan., they probably found even action, but the line moving down suggested they had uneven Tulane action.
