They can still be of their faiths, not every religious person is a fundamentalist. Like how Bruce Lee began mixing the better parts of martial arts and pissed off the Kung-Fu and Karate purists. Adaptation is my faith, it's the only way we will evolve as a species, to one day become universal beings. If anything I like to think we are all god trying to pull itself back together again and our evolution is us working our way back up to god status until one day we are all on that wavelength where it all just clicks and there comes the universal A-HA! moment...
I understand people wanting to believe that "we" as humans have to have another purpose then just life here in these current forms but there simply is no proof of that other than belief systems. personally it puts me at ease to think some day all of this will come to an end.
it really fucking bothers me when religious people happen to be some of the biggest hypocrites as is the entire history of Christianity as when the popes ordered the killing of people in the 1300's CE, etc.
in terms of history and "proof" every bad thing that has occurred to humans on planet earth has been done by other humans. we are the ones that make things good or bad events occur and not "the devil", etc.
the "need" to be worshiped sounds rather petty for a creator of worlds and the universe. a supreme being has no need of such, it's humans that need their egos to get stroked and some more than others.
as time goes by we learn more and more about life on earth and science. I mean who would have ever thought that a person could die from drinking too much water 15-20 years ago? I certainly didn't. but we have seen people do it in recent years during contests, etc.
there have been thousands of religions over the lifetime of humans on this planet and they all come and go.