As for the "Cruz is the smartest person in the room" thing, it's a criticism people in Washington who don't like him created. It's how they describe him and it's why they don't like him. Nobody likes it when somebody who knows their job better than they do shows up.

This is also part of why they don't like Trump, but for different reasons. Trump isn't smarter than them on policy nor on Washington politics the way Cruz is. But he is smarter than them on electoral politics, apparently.