That's incorrect. The phone has a built in throttle that only draws the amount of amperage out needs. Kinda like a water hose with a valve at the end, regardless how much flow is available, the valve controls how much is let through. While a stronger charger wouldn't charge the battery faster, I do like them for greater versatility across devices and it would theoretically last longer because it isn't working as hard to deliver the same power as a weaker one.
EDIT: Probably a better analogy would be the 110V wall outlet. Those are typically 30 amp circuits, but you don't see them damaging small devices (defects aside of course).