To be alive on this planet a person has to have faith. It does not have to be a faith in God, but it does have to be a faith in something.
To drive in a car safely we have to show faith in the other drivers. To fly in a plane we have to have faith in the pilots and the mechanics.
There are actually many levels which faith is necessary; faith in yourself, your relationship with your spouse, your family, community, country, and so on. Faith must be maintained on all of these levels concurrently for life to go along smoothly.
However, it is only at the highest level do we fight over whether faith is necessary or not.