Let me be as clear as I can be: the iOS multitasking bar does not contain “a list of all running apps”. It contains “a list of recently used apps”. The user never has to manage background tasks on iOS.
He goes on to give an excellent breakdown of how iOS manages apps and memory. I’ve also heard from clients that the Apple Store’s Genius Bar told them to manually quit apps to make their iPhone run faster.
Bottom line: this is complete nonsense which should be ignored.