the epic of Ramayana is not just to show God's powers but also teach something to all of us. Lord Rama could have destroyed Ravana in a second if he wanted but wanted to show how a human being should be. That is why he took the Avatar of Rama. By building the bridge, he showed how teamwork, be it as little as a squirrel's effort matters to achieve good for everyone. Unfortunately for non-believers or so called critics, it is not easy to see the inner meaning beyond surface level reading. Each incident of Ramayana and for that matter all of God's actions have a deep meaning for us to understand.
