Seattle may get less total precipitation than those other cities, but it gets more rainy days.
In all seriousness, I'd prefer to hedge and allow that 2 billion people might be right than to declare the out-and-out truth.
So... if the debate that Aesthus is referring to is the one between phylogenetic classification and Linnaean classification (I know it's not, but just for the sake of argument)... then he's actually correct. You could say that humans did, in fact, live alongside dinosaurs. And they still do today.