It's an explanation of how monkeys and humans could both have evolved. Everything about the world hasn't been figured out yet, so different explanations have been made -- some false, some true.
If different isolated groups evolve differently, that validates the claim in the yahoo post. This isn't just a mere opinion, but an a posteriori reasoning.
If you want proof, here are five: http://evolutionfaq.com/articles/five-proofs-evolution