The same blog site has confirmed the legitimacy of the e-mail after verifying if the address was indeed of the SVP.

People have been constantly in conflict with this issue, and Federighi's response can be considered the strongest clarification that users could ever ask for. The Apple executive's response is nothing more but a confirmation from what the Apple support pages already have regarding the myth - that there is only a need to force quit an application when it freezes or fails to work properly. After all, when they are in the background, they enter standby mode, which does not use RAM or any other system resource.

Phone battery performance has always been a complaint from users, and apps have been associated with causing quicker battery draining. However, apps that actually eat large battery charges are GPS navigation, music players and anything similar to these apps. These apps are those that you actually open when you are using them. These are different from the background apps that go on suspended mode when no longer in use, and those are the apps that are unnecessary to force quit.